12 the periodic table compression guide: chapter · pdf file12.. periodic reading-----chapter...

OBJECTIVES LABS, DEMONSTRATIONS, AND ACTIVITIES TECHNOLOGY RESOURCES

Compression guide:To shorten instructionbecause of time limitations,omit the Chapter Lab.

12 The Periodic TableChapter Planning Guide

Chapter Opener

333A Chapter 12 • The Periodic Table

OSP Lesson Plans (also in print)TR Bellringer Transparency*

TR P109 The Periodic Table of theElements*

CRF SciLinks Activity*gVID Lab Videos for Physical Science TE Internet Activity, p. 341gCD Science Tutor

TE Demonstration Grouping, p. 336g TE Activity Element Sampling, p. 337 ◆g

TE Activity Looking for Gaps, p. 339a SE Quick Lab Conduction Connection, p. 340 ◆g

CRF Datasheet for Quick Lab* TE Activity Element Game, p. 340b TE Activity Elements Everywhere, p. 341g SE School-to-Home Activity Patterns of Symbols,

p. 342g SE Model-Making Lab Create a Periodic Table,

p. 352 ◆g

CRF Datasheet for Chapter Lab*

Section 1 Arranging the Elements• Describe how Mendeleev arranged elements in the

first periodic table.• Explain how elements are arranged in the modern

periodic table.• Compare metals, nonmetals, and metalloids based

on their properties and on their location in theperiodic table.

• Describe the difference between a period anda group.

OSP Lesson Plans (also in print)TR Bellringer Transparency*

TR LINK TOLINK TO LIFE SCIENCELIFE SCIENCE L79 TheSkeleton*

SE Internet Activity, p. 348g CD Interactive Explorations CD-ROM

Element of SurprisegCD Science Tutor

TE Connection Activity Math, p. 347g TE Connection Activity History, p. 348a SE Connection to Biology Water Treatment, p. 349g LB Whiz-Bang Demonstrations Waiter, There’s Carbon in

My Sugar Bowl!*b LB Inquiry Labs The Chemical Side of Light*g LB Long-Term Projects & Research Ideas

It’s Element-ary*a SE Science in Action Math, Social Studies, and Language

Arts Activities, pp. 358–359g

PACING • 45 min pp. 344–351Section 2 Grouping the Elements• Explain why elements in a group often have similar

properties.• Describe the properties of the elements in the groups

of the periodic table.

OSP Parent Letter ■

CD Student Edition on CD-ROM CD Guided Reading Audio CD ■

TR Chapter Starter Transparency*VID Brain Food Video Quiz

SE Start-up Activity, p. 335 ◆gpp. 334–343PACING • 135 min

CRF Vocabulary Activity*g SE Chapter Review, pp. 354–355g

CRF Chapter Review* ■g

CRF Chapter Tests A* ■g, B*a, C*s SE Standardized Test Preparation, pp. 356–357g

CRF Standardized Test Preparation*gCRF Performance-Based Assessment*gOSP Test Generator, Test Item Listing

CHAPTER REVIEW, ASSESSMENT, ANDSTANDARDIZED TEST PREPARATION

PACING • 90 min

Online and Technology Resources

Visit go.hrw.com foraccess to Holt OnlineLearning, or enter thekeyword HP7 Homefor a variety of freeonline resources.

This CD-ROM package includes:• Lab Materials QuickList Software• Holt Calendar Planner• Customizable Lesson Plans• Printable Worksheets

• ExamView® Test Generator• Interactive Teacher’s Edition• Holt PuzzlePro®

• Holt PowerPoint® Resources

STANDARDS CORRELATION SKILLS DEVELOPMENT RESOURCES SECTION REVIEW AND ASSESSMENT CORRELATIONS

Chapter 12 • Chapter Planning Guide 333B

CRF Directed Reading A* ■b, B*s IT Interactive Textbook* Struggling ReadersStruggling Readers

CRF Vocabulary and Section Summary* ■g

SE Reading Strategy Mnemonics, p. 336g SE Connection to Language Arts Hidden Help, p. 337g TE Reading Strategy Discussion, p. 338g TE Support for English Language Learners, p. 338 TE Inclusion Strategies, p. 339 SE Math Practice Percentages, p. 341g

SE Reading Checks, pp. 336, 337, 340, 342g TE Homework, p. 337g TE Reteaching, p. 342b TE Quiz, p. 342g SE Section Review,* p. 343 ■g

TE Alternative Assessment, p. 343gCRF Section Quiz* ■g

UCP 1; SAI 2; SPSP 5; HNS 1, 2,3; PS 1b; Chapter Lab: UCP 1;SAI 1, 2

CRF Directed Reading A* ■b, B*s IT Interactive Textbook* Struggling ReadersStruggling Readers

CRF Vocabulary and Section Summary* ■g

SE Reading Strategy Paired Summarizing, p. 344g TE Inclusion Strategies, p. 344 TE Support for English Language Learners, p. 345 SE Connection to Environmental Science Recycling Aluminum,

p. 347g MS Math Skills for Science Checking Division with Multiplication*g SS Science Skills Finding Useful Sources*gCRF Reinforcement Worksheet Placing All Your Elements on the

Table*bCRF Critical Thinking Believe It or Not*a

SE Reading Checks, pp. 345, 346, 347, 348,350g

TE Homework, p. 349a TE Reteaching, p. 350b TE Quiz, p. 350g SE Section Review,* p. 351 ■ g

TE Alternative Assessment, p. 351gCRF Section Quiz* ■g

ST 2; PS 1b, 3e

SE Pre-Reading Activity, p. 334gOSP Science Puzzlers, Twisters & Teasersg

National ScienceEducation Standards

UCP 1, 2; SAI 1; ST 2; SPSP 5;HNS 1, 3

CRF Chapter Resource File SS Science Skills Worksheets IT Interactive TextbookOSP One-Stop Planner MS Math Skills for Science Worksheets * Also on One-Stop Planner

SE Student Edition LB Lab Bank CD CD or CD-ROM ◆ Requires advance prepTE Teacher Edition TR Transparencies VID Classroom Video/DVD ■ Also available in Spanish

KEY

Maintained by the NationalScience Teachers Association.See Chapter Enrichment pagesthat follow for a complete listof topics.

www.scilinks.orgCheck out Current Sciencearticles and activities byvisiting the HRW Web siteat go.hrw.com. Just typein the keyword HP5CS12T.

• Lab Videos demonstratethe chapter lab.

• Brain Food Video Quizzeshelp students review thechapter material.

ClassroomVideos

Holt Lab GeneratorCD-ROM

Search for any lab by topic, standard,difficulty level, or time. Edit any labto fit your needs, or create your ownlabs. Use the Lab Materials QuickListsoftware to customize your labmaterials list.

• Guided Reading Audio CD(Also in Spanish)

• Interactive Explorations• Virtual Investigations• Visual Concepts• Science Tutor

ClassroomCD-ROMs

Planning ResourcesTEST ITEM LISTINGPARENT LETTERLESSON PLANS

Visual ResourcesBELLRINGER

TRANSPARENCIES TEACHING TRANSPARENCIESCHAPTER STARTER

TRANSPARENCY

TEACHING TRANSPARENCIESCONCEPT MAPPING

TRANSPARENCY

TEST ITEM LISTING

Copyright © by Holt Rinehart and Winston All rights reserved

The World of ScienceMULTIPLE CHOICE

1. A limitation of models is thata. they are large enough to see.b. they do not act exactly like the things that they model.c. they are smaller than the things that they model.d. they model unfamiliar things.Answer: B Difficulty: I Section: 3 Objective: 2

2. The length 10 m is equal toa. 100 cm. c. 10,000 mm.b. 1,000 cm. d. Both (b) and (c)Answer: B Difficulty: I Section: 3 Objective: 2

3. To be valid, a hypothesis must bea. testable. c. made into a law.b. supported by evidence. d. Both (a) and (b)Answer: B Difficulty: I Section: 3 Objective: 2 1

4. The statement "Sheila has a stain on her shirt" is an example of a(n)a. law. c. observation.b. hypothesis. d. prediction.Answer: B Difficulty: I Section: 3 Objective: 2

5. A hypothesis is often developed out ofa. observations. c. laws.b. experiments. d. Both (a) and (b)Answer: B Difficulty: I Section: 3 Objective: 2

6. How many milliliters are in 3.5 kL?a. 3,500 mL c. 3,500, 000 mLb. 0.0035 mL d. 35,000 mLAnswer: B Difficulty: I Section: 3 Objective: 2

7. A map of Seattle is an example of aa. law. c. model.b. theory. d. unit.Answer: B Difficulty: I Section: 3 Objective: 2

8. A lab has the safety icons shown below. These icons mean that you should weara. only safety goggles. c. safety goggles and a lab apron.b. only a lab apron. d. safety goggles, a lab apron, and gloves.Answer: B Difficulty: I Section: 3 Objective: 2

9. The law of conservation of mass says the tot al mass before a chemical change isa. more than the total mass after the change.b. less than the total mass after the change.c. the same as the total mass after the change.d. not the same as the total mass after the change.Answer: B Difficulty: I Section: 3 Objective: 2

10. In which of the following areas might you find a geochemist at work?a. studying the chemistry of rocks c. studying fishesb. studying forestry d. studying the atmosphereAnswer: B Difficulty: I Section: 3 Objective: 2

TEACHER RESOURCE PAGE

Lesson Plan

Section: Waves

PacingRegular Schedule: with lab(s):2 days without lab(s):2 days

Block Schedule: with lab(s): 1 1/2 days without lab(s): 1 day

Objectives1. Relate the seven properties of life to a living organism.

2. Describe seven themes that can help you to organize what you learn aboutbiology.

3. Identify the tiny structures that make up all living organisms.

4. Differentiate between reproduction and heredity and between metabolismand homeostasis.

National Science Education Standards CoveredLSInter6: Cells have particular structures that underlie their functions.

LSMat1: Most cell functions involve chemical reactions.

LSBeh1:Cells store and use information to guide their functions.

UCP1:Cell functions are regulated.

SI1: Cells can differentiate and form complete multicellular organisms.

PS1: Species evolve over time.

ESS1: The great diversity of organisms is the result of more than 3.5 billion yearsof evolution.

ESS2: Natural selection and its evolutionary consequences provide a scientificexplanation for the fossil record of ancient life forms as well as for the strikingmolecular similarities observed among the diverse species of living organisms.

ST1: The millions of different species of plants, animals, and microorganismsthat live on Earth today are related by descent from common ancestors.

ST2: The energy for life primarily comes from the sun.

SPSP1: The complexity and organization of organisms accommodates the needfor obtaining, transforming, transporting, releasing, and eliminating the matterand energy used to sustain the organism.

SPSP6: As matter and energy flows through different levels of organization ofliving systems—cells, organs, communities—and between living systems and thephysical environment, chemical elements are recombined in different ways.

HNS1: Organisms have behavioral responses to internal changes and to externalstimuli.

This CD-ROM includes all of theresources shown here and thefollowing time-saving tools:

• Lab Materials QuickListSoftware

• Customizable lesson plans

• Holt Calendar Planner

•The powerfulExamView® TestGenerator

Chapter Resources

Dear Parent,

Your son's or daughter's science class will soon begin exploring the chapter entitled “The

World of Physical Science.” In this chapter, students will learn about how the scientific

method applies to the world of physical science and the role of physical science in the

world. By the end of the chapter, students should demonstrate a clear understanding of the

chapter’s main ideas and be able to discuss the following topics:

1. physical science as the study of energy and matter (Section 1)

2. the role of physical science in the world around them (Section 1)

3. careers that rely on physical science (Section 1)

4. the steps used in the scientific method (Section 2)

5. examples of technology (Section 2)

6. how the scientific method is used to answer questions and solve problems (Section 2)

7. how our knowledge of science changes over time (Section 2)

8. how models represent real objects or systems (Section 3)

9. examples of different ways models are used in science (Section 3)

10. the importance of the International System of Units (Section 4)

11. the appropriate units to use for particular measurements (Section 4)

12. how area and density are derived quantities (Section 4)

Questions to Ask Along the Way

You can help your son or daughter learn about these topics by asking interesting questions

such as the following:

• What are some surprising careers that use physical science?

• What is a characteristic of a good hypothesis?

• When is it a good idea to use a model?

• Why do Americans measure things in terms of inches and yards instead of centimeters

and meters ?

333C Chapter 12 • The Periodic Table

12

Would YouBelieve . . . ?Suppose someone told you that the small animalshown above—a yellow-spotted rock hyrax—isgenetically related to an elephant. Impossible,you say? But it’s true! Even though this animallooks more like a rabbit or a rodent, scientistshave determined through DNA studies that theclosest relatives of the hyrax are aardvarks, seacows, and elephants. Biologists have uncoveredsimilar genetic links between other seeminglydifferent species.

Scientists have also discovered that manydifferent-looking elements, like those shown atright, actually have common properties. For almost150 years, scientists have organized elements byobserving the similarities (both obvious and notso obvious) between them. One scientist inparticular—a Russian named Dmitri Mendeleev(MEN duh LAY uhf )—organized the known elementsin such a way that a repeating pattern emerged.Mendeleev actually used this patternto predict the properties of elementsthat had not even been discovered! Hismethod of organization becameknown as the periodic table.

The modern periodic table isarranged somewhat differently thanMendeleev’s, but it is still a useful toolfor organizing the known elements andpredicting the properties of elementsstill unknown. Read on to learn aboutthe development of this remarkabletable and the patterns it reveals.

The Periodic Table CHAPTER STARTER

Although solid iodine and liquid bromine havevery different appearances, they have similarchemical properties.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

The Periodic Table BELLRINGER TRANSPARENCY


Section: Arranging the ElementsThink of all the ways a deck of cards could be laidout so that the cards form some sort of identifiablepattern. Illustrate your answers in your science

journal. Write out as many different patterns as youcan.

Section: Grouping the ElementsThink about the following: How do you know a birdis a bird? a kangaroo is a kangaroo? a shark is ashark? What characteristics of each animal help youto tell them apart? How does this apply to elements?

Record your answers in your science journal.

140.1

232.0

140.9

231.0

144.2

238.0

(145)

(237)

150.4

(244)

6.9

23.0

39.1

85.5

132.9

9.0

24.3

40.1

87.6

137.3

(226)

45.0

88.9

138.9

(227)

47.9

91.2

178.5

(261)

50.9

92.9

180.9

(262)

52.0

95.9

183.8

(266)

54.9

(98)

186.2

(264)

55.8

101.1

190.2

(277)

58.9

102.9

192.2

(268)

1.0

Praseodymium

Rutherfordium

Molybdenum

Lithium

Sodium

Potassium

Rubidium

Cesium

Cerium

ThoriumProtactinium

Neodym

ium

Uranium

Promethium

Neptunium

Samarium

Plutonium

Beryllium

Magnesium

Calcium

Strontium

Barium

Radium

Scandium

Yttrium

Lanthanum

Actinium

Titanium

Zirconium

Hafnium

Vanadium

Niobium

Tantalum

Dubnium

Chrom

ium

Tungsten

Seaborgium

Manganese

Technetium

Rhenium

Bohrium

Iron

Ruthenium

Osm

ium

Hassium

Cobalt

Rhodium

Iridium

Meitnerium

Hydrogen

Li

V

NaKRb

Cs

Fr

Be

Mg

Ca

Sr

Ba

Ra

ScYLa

Ac

Ti

Zr

Hf

Rf

Nb

Ta

Db

Cr

Mo

WSg

Mn

Re

Bh

IrO

s

Ce

Th

Pr

Pa

NdU

PmNp

SmPu

Fe

Ru

Hs

Co

Rh

Mt

H

Tc

31119375587

5890

5991

6092

6193

6294

41220385688

21395789

224072

104

234173

105

244274

106

254375

107

26447677

108

2745

109

1

Group 3

Group 4

Group 5

Group 6

Group 7

Group 8

Group 9

Group 1

Group 2

Period 1

Period 2

Period 3

Period 4

Period 5

Period 6

Period 7

Lanthanides

Background

Metals

Metalloids

Nonm

etals

Chemical sym

bol

Solid

Liquid

Gas

6CThe color of thechem

ical sym-

bol indicates thephysical state atroom

temperature.

Carbon is a solid.

The background color indicates thetype of elem

ent. Carbon is a nonm

etal.

These elements are placed

below the table to allow

the table to be narrower.

A column of

elements is called

agroup or

family.

Ato

mic n

um

ber

Ch

emical sym

bo

l

Elemen

t nam

e

Ato

mic m

ass

A row of

elements is

called aperiod.

Values in parentheses are the mass num

bers of thoseradioactive elem

ents’ most stable or m

ost comm

on isotopes.

Periodic

Table o

f the

Elements

Each square on the table includes anelem

ent’s name, chem

ical symbol,

atomic num

ber, and atomic m

ass.


152.0

(243)

157.2

(247)

158.9

(247)

162.5

(251)

164.9

(252)

167.3

(257)

168.9

(258)

173.0

(259)

175.0

(262)

58.763.5

65.469.7

72.674.9

79.079.9

83.8

27.028.1

31.032.1

35.539.9

10.812.0

14.016.0

19.020.2

4.0

106.4107.9

112.4114.8

118.7121.8

127.6126.9

131.3

195.1

(281)(272)

197.0200.6

204.4207.2

209.0(209)

(210)(222)

(285)(289)

(288)(284)

Europium

Am

ericium

Gadolinium

Curium

Terbium

Berkelium

Dysprosium

Californium

Holm

ium

Einsteinium

Erbium

Fermium

Thulium

Mendelevium

Ytterbium

Nobelium

Lutetium

Lawrencium

Nickel

Copper

ZincG

alliumG

ermanium

Arsenic

SeleniumB

romine

Krypton

Alum

inumSilicon

PhosphorusSulfur

Chlorine

Argon

Boron

Carbon

Nitrogen

Oxygen

FluorineN

eon

Helium

PalladiumSilver

Cadm

iumIndium

TinA

ntimony

TelluriumIodine

Xenon

Darm

stadtiumU

nununium

PlatinumG

oldM

ercuryThallium

LeadB

ismuth

PoloniumA

statineR

adon

Ununbium

Ununquadium

Ununpentium

Ununtrium

Eu

Am

Gd

Cm

Tb

Bk

Dy

Cf

Pd

Ag

Cd

InSn

SbT

eI

Xe

Pt

Ds

Uu

u

Au

Hg

Tl

Pb

Bi

Po

At

Rn

Ho

Es

Er

Fm

Tm

Md

Yb

No

Lu

Lr

Ni

Cu

Zn

Ga

Ge

As

SeB

rK

r

Al

Si

PS

Cl

Ar

BC

NO

FN

e

He

Uu

bU

uq

Uu

pU

ut

2829

3031

3233

3435

36

1314

1516

1718

56

78

910 2

4647

4849

5051

5253

54

7879

8081

8283

8485

86

110111

6395

6496

6597

6698

6799

68

100

69

101

70

102

71

103

112114

115113

Group 13

Group 14

Group 15

Group 16

Group 17

Group 18

Group 10

Group 11

Group 12

The discovery of elements

113, 114, and 115 has beenreported but not confirm

ed.

This zigzag linerem

inds you where

the metals, nonm

etals,and m

etalloids are.

The names and three-letter sym

bols of elements are tem

porary. Theyare based on the atom

ic numbers of the elem

ents. Official nam

es andsym

bols will be approved by an international com

mittee of scientists.

The Periodic TableTEA

CHIN

G TR

AN

SPAR

ENCY

The Periodic Table of the Elements

P109

arranged in

is a chart of

metalloids

in which thenumber of

that areclassified as

rowscalled

columnscalled

increases fromleft to right

The Periodic Table CONCEPT MAPPING TRANSPARENCY


Use the following terms to complete the concept map below:elements, periods, metals, electrons, nonmetals, periodic table,familiesThe Skeleton


TEACH

ING

TRA

NSPA

REN

CY

Protection

Your heartand lungs are protectedby ribs, your spinal cordis protected by verte-brae, and your brain isprotected by the skull.

StorageB

ones storem

inerals that help yournerves and m

usclesfunction properly. Longbones store fat that canbe used for energy.

Movem

ent

Skeletalm

uscles pull on bonesto produce m

ovement.

Without bones, you

would not be able to sit,

stand, walk, or run.

Blood

Cell Formation

Some of your bones

are filled with a special

material that m

akesblood cells. This m

aterialis called

marrow

.

Femur

Pelvicgirdle

Vertebralcolum

n

Patella

Tibia

Fibula

Ulna

Radius

Skull

Ribs

Clavicle

Hum

erus

L79

Chapter: Body Organization and Structure

SAMPLE SAMPLE SAMPLE

Meeting Individual Needs

Review and Assessments

Labs and Activities

DIRECTED READING A VOCABULARY ACTIVITY REINFORCEMENT

INQUIRY LABS

STANDARDIZED TEST PREPARATIONCHAPTER TEST BCHAPTER REVIEWSECTION QUIZ

SCILINKS ACTIVITY

MARINE ECOSYSTEMS

Go to www.scilinks.com. To find links relatedto marine ecosystems, type in the keywordHL5490. Then, use the links to answer thefollowing questions about marine ecosys-tems.

1. What percentage of the Earth’s surface iscovered by water?

2. What percentage of the Earth’s water is found in the oceans?

3. What is the largest animal on Earth?

4. Describe an ocean animal.

Name Class Date

SciLinks ActivityActivity

Developed and maintained by theNational Science Teachers Association

Topic: Reproductive SystemIrregularitiesSciLinks code: HL5490

WHIZ-BANGDEMONSTRATIONS


Name Class Date

Vocabulary ActivityActivity

Getting the Dirt on the SoilAfter you finish reading Chapter: [Unique Title], try this puzzle! Use the clues belowto unscramble the vocabulary words. Write your answer in the space provided.

1. the breakdown of rock intosmaller and smaller pieces:AWERIGNETH

2. layer of rock lying beneath soil:CROKDEB

3. type of crop that is plantedbetween harvests to reduce soilerosion: CROVE

4. action of rocks and sedimentscraping against each other andwearing away exposed surfaces:SABRONIA

5. a mixture of small mineral frag-ments and organic matter: LISO

6. rock that is a source of soil:PRATEN CORK

7. type of reaction that occurs whenoxygen combines with iron toform rust: oxidation

8. type of weathering caused byphysical means: CLEMANIACH

9. the chemical breakdown of rocksand minerals into new substances: CAMILCHETHEARIGWEN

10. layers of soil, to a geologist:SNORHIZO

11. the uppermost layer of soil:SPOTOIL

12. process in which rainwater car-ries dissolved substances fromthe uppermost layers of soil to thebottom layers: HELANCIG

13. small particles of decayed plantand animal material in soil:MUUSH

14. the process in which wind, water,or ice moves soil from one location to another: ROOSINE

15. the methods humans use to takecare of soil:OSIL VASETONRICON

LONG-TERM PROJECTS & RESEARCH IDEAS

DATASHEETS FOR QUICKLABS

DATASHEETS FOR QUICK LABS

VOCABULARY AND SECTION SUMMARY


Section: EnergIn the space provided, write the letter of the description that best matches theterm or phrase.

______ 1. building molecules that can be used asan energy source. or breaking down moleculesin which energy is stored

______ 2. the process by which light energy is convertedto chemical energy

______ 3. an organism that uses sunlight or inorganicsubstances to make organic compounds

______ 4. an organism that uses sunlight or inorganicsubstances to make organic compounds

______ 5. an organism that consumes food to get energy

______ 6. the process of getting energy from food

In the space provided, write the letter of the term or phrase that best completeseach statement or best answers each question.

Name Class Date

Section QuizAssessment

a. photosynthesis

b. autotroph

c. heterotroph

d. cellular respiration

e. metabolism

f. cellular respiration

______ 7. Which of the following mostclosely resembles cellularrespiration?a. warm water moving

through copper pipesb. people movimg alomg a

escalatorc. mixing different foods in

a blenderd. logs burning in a fire

______ 8. An organism’s reproductivecells, such as sperm or eggcells, are called?a. genesb. chromosomesc. gamates.d. zygotes.

______ 9. An organism’s reproductivecells, such as sperm or eggcells, are called?a. genesb. chromosomesc. gamates.d. zygotes.

______10. Which of the following mostclosely resembles cellularrespiration?a. warm water moving

through copper pipesb. people movimg alomg a

escalatorc. mixing different foods in

a blenderd.

logs burning in a fire


Section: ExploringTHAT’S SCIENCE!

1. How did James Czarnowski get his idea for the penguin boat, Proteus?Explain.

2. What is unusual about the way that Proteus moves through the water?

MATTER + AIR ➔ PHYSICAL SCIENCE

3. What do air, a ball, and a cheetah have in common?

4. What is one question you will answer as you explore physical science?

5. Chemistry and physics are both fields of . Chemists

study the different forms of and how they interact.

and how it affects are

studied in physics.

Identify the field of physical science to which each of the following descriptionsbelongs by writing physics or chemistry in the space provided.

_______________________ 6. how a compass works

_______________________ 7. why water boils at 100°C

_______________________ 8. how chlorine and sodium combine to form table salt

_______________________ 9. why you move to the right when the car you are inturns left

Directed Reading A

Name Class Date

Skills Worksheet

DIRECTED READING B

Section: ExploringTHAT’S SCIENCE!

1. How did James Czarnowski get his idea for the penguin boat, Proteus?Explain.

2. What is unusual about the way that Proteus moves through the water?

MATTER + AIR ➔ PHYSICAL SCIENCE

3. What do air, a ball, and a cheetah have in common?

Directed Reading B

Name Class Date

Skills Worksheet

Section: UniqueVOCABULARY

In your own words, write a definition of the following term in the space provided.

1. scientific method

2. technology

3. observation

Name Class Date

Vocabulary & NotesSkills Worksheet

Name Class Date

ReinforcementSkills Worksheet

The Plane TruthComplete this worksheet after you finish reading the Section: [Unique SectionTitle]

You plan to enter a paper airplane contest sponsoredby Talkin’ Physical Science magazine. The personwhose airplane flies the farthest wins a lifetime sub-scription to the magazine! The week before the con-test, you watch an airplane landing at a nearbyairport. You notice that the wings of the airplane haveflaps, as shown in the illustration at right. The paperairplanes you’ve been testing do not have wing flaps.What question would you ask yourself based on these observations? Write yourquestion in the space below for “State the problem.” Then tell how you could usethe other steps in the scientific method to investigate the problem.

1. State the problem.

2. Form a hypothesis.

3. Test the hypothesis.

4. Analyze the results.

5. Draw conclusions.

Flaps


CRITICAL THINKING

A Solar Solution

Name Class Date

Critical Thinking Skills Worksheet

Joseph D. Burns

Inventors’ Advisory Consultants

Portland, OR 97201

Dear Mr. Burns,I’ve got this great idea for a new product called the BlissHeater. It’s a portable, solar-powered space heater. The heater’s design includes these features:•T

he heater will be as longas an adult’s arm and aswide as a

packing box.

•T

he heater will have aglass top set at an angleto catch the sun’s rays.

•T

he inside of the heaterwill be dark colored toabsorb solar heat.If you think my idea will work, I will make the Bliss

Heaters right away without wasting time and money on test-ing and making models. Please write back soon with youropinion.

SECTION REVIEW

Section: UniqueKEY TERMS

1. What do paleontologist study?

2. How does a trace fossil differ from petrified wood?

3. Define fossil.

UNDERSTANDING KEY IDEAS

Name Class Date

Section ReviewSkills Worksheet


[UniqueMULTIPLE CHOICE


______ 1. Surface currents are formed by a. the moon’s gravity. c. wind.b. the sun’s gravity. d. increased water density.

______ 2. When waves come near the shore, a. they speed up. c. their wavelength increases.b. they maintain their speed. d. their wave height increases.

______ 3. Longshore currents transport sediment a . out to the open ocean. c. only during low tide.b. along the shore. d. only during high tide.

______ 4. Which of the following does NOT control surface currents?a. global wind c. Coriolis effectb. tides d. continental deflections

______ 5. Whitecaps break a. in the surf. c. in the open ocean.b. in the breaker zone. d. as their wavelength increases.

______ 6. Most ocean waves are formed by a . earthquakes. c. landsides.b. wind. d. impacts by cosmic bodies.

______ 7. Which factor controls surface currents? a. global winds c. continental deflectionb. the Coriolis effect d. all of the above

______ 8. Streamlike movments of ocean water far below the surface arecalleda. jet currents c. surface currents.b. Coriolis currents. d. deep currents.

______ 9. When the sunlit part of the moon that can be seen from Earthgrows larger, it is a. waxing. c. in the new moon phase.b. waning. d. in the full moon phase.

______10. The Milky Way is thought to be a. an elliptical galaxy. c. a spiral galaxy.

Name Class Date

Chapter Test BAssessment


READING

Read the passages below. Then, read each question that follows the passage.Decide which is the best answer to each question.

Passage 1 adventurous summer camp in the world. Billy can’twait to head for the outdoors. Billy checked the recommendedsupply list: light, summer clothes; sunscreen; rain gear; heavy,down-filled jacket; ski mask; and thick gloves. Wait a minute! Billythought he was traveling to only one destination, so why does heneed to bring such a wide variety of clothes? On further investiga-tion, Billy learns that the brochure advertises the opportunity to“climb the biomes of the world in just three days.” The destinationis Africa’s tallest mountain, Kilimanjaro.

______ 1. The word destination in this passage means A camp B vacation.C place. D mountain.

______ 2. Which of the following is a FACT in the passage? F People ski on Kilimanjaro.G Kilimanjaro is Africa’s tallest mountain.H It rains a lot on Kilimanjaro.J The summers are cold on Kilimanjaro.

______ 3. Billy wondered if the camp was advertising only one destination afterhe read the brochure, which said thatA the camp was the most adventurous summer camp in the world. B he would need light, summer clothes and sunscreen.C he would need light, summer clothes and a heavy, down-filled

jacket.D the summers are cold on Kilimanjaro.

Name Class Date

Standardized Test PreparationAssessment

PERFORMANCE-BASEDASSESSMENT

OBJECTIVEDetermine which factors cause some sugar shapes to break down faster than others.

KNOW THE SCORE!As you work through the activity, keep in mind that you will be earning a gradefor the following:

• how you form and test the hypothesis (30%)

• the quality of your analysis (40%)

• the clarity of your conclusions (30%)

ASK A QUESTIONSWhy do some sugar shapes erode more rapidly than others?

MATERIALS AND EQUIPMENT

Name Class Date

Performanced-Based AssessmentAssessment SKILL BUILDER

Using Scientific Methods

• 1 regular sugar cube • 90 mL of waterCopyright © by Holt, Rinehart and Winston. All rights reserved.

USING VOCABULARY

1. Define biome in your own words.

2. Describe the characteristics of a savanna and a desert.

3. Identify the relationship between tundra and permafrost.

4. Compare the open-water zone and the deep-water zone.

5. Use each of the following terms in an original sentence: plankton, littoralzone, and estuary.

6. Describe how marshes and swamps differ.

Name Class Date

Chapter ReviewSkills Worksheet

SCIENCE PUZZLERS, TWISTERS & TEASERS

CHAPTER TEST A






______ 4. Which of the following does NOT control surface currents?a global wind c Coriolis effect

Name Class Date

Chapter Test AAssessment

CHAPTER TEST C






______ 4. Which of the following does NOT control surface currents?a global wind c Coriolis effect

Name Class Date

Chapter Test CAssessment

Chapter 12 • Chapter Resources 333D

Periodic Crime1. This is an eyewitness account of a crime recently committed.

Which element committed the crime?

“He was definitely a metal, but really soft, like you could cut himwith a knife. As he ran past us, we squirted him with a water gun.He burst into flame! It was unbelievable. We almost had him cor-nered, but he pulled out a vile of chlorine gas and in the blink ofan eye, he disappeared. All that was left was a pile of table salt.”

Elements in the Round2. Moving from the outside of the circle to the center of the circle,

choose one letter from each ring to find the names of eight com-mon elements. Write the names of the elements on the lines pro-vided. Each letter will be used only once.

Name _______________________________________________ Date ________________ Class______________

SCIENCE PUZZLERS, TWISTERS & TEASERS12

The Periodic Table

CHAPTER

I

The history of the periodic table is like a detective story that spans many centuries.Although most of the elements on Earth have been around for billions of years,scientists have had to do some sleuthing to find each element’s unique identity.

The ancient Greeks knew nine elements, including gold, sulfur, copper, and car-bon. These elements, which are found in almost pure form as minerals, are callednative elements. In 1669, Hennig Brand was the first scientist to actively search forand isolate an element. It was phosphorus. After that, many other scientists lookedfor other elements. In fact, seventy-four other elements were discovered between1737 (cobalt) and 1925 (rhenium). The contributions of history’s “elemental”detectives have helped build the modern periodic table—a chemist’s best friend.

Periodic Changes1. Find older versions of the periodic table in textbooks and

encyclopedias from the last 75 years. How has the periodictable changed? How is it the same? On a modern periodictable, label the dates when 10 of the elements were discov-ered. How are new elements discovered and added to theperiodic table? Write a report and make a poster display toillustrate your findings.

Research Ideas2. Each element has a story to tell. Pick one element from

the periodic table to research. When was it discovered?How did the element get its name? What are its proper-ties? What are its uses? Is the element found in any com-mon materials? How is it obtained? Report your findingsin the form of a story written from the element’s point of view.

3. That’s a killer element! Some transition metals, includingcadmium, nickel, mercury, and lead, are hazardous tohuman health. Find out more about how these elementsare used and why they are dangerous. Write a brochurethat outlines the precautions one should take to preventpoisoning people and polluting the environment whenusing these metals.

4. Did you know that your blood is full of metal? Your bodyneeds iron to stay healthy. Most of the iron in the body is found in hemoglobin, the chemical in red blood cellsthat carries oxygen and carbon dioxide in your blood.Find out more about the properties of elemental iron andthe compound hemoglobin. How much iron do you needdaily? Where do you get iron in your diet? Write yourfindings in the form of a magazine article.

Name ___________________________________________________ Date _________________ Class _____________

PROJECT

STUDENT WORKSHEET62

It’s Element-ary

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HELPFUL HINT

Try searching for thename of the metal, plus the word toxicity,poisoning, or elemental.For example, you mightsearch for cadmium tox-icity or lead poisoning.

John Dalton’sTable of Elements,1808

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TEACHER-LED DEMONSTRATION

DEMO

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Purpose

Students will draw a connection betweenorganic matter and its fundamental ele-ment, carbon, as they view a spectacularchemical reaction. They will learn aboutchemical changes and prove that sugarcontains carbon.

Time Required

10–15 minutes

Safety Information

Use extreme caution while performing thisdemonstration. Sulfuric acid is extremelycaustic and can damage body tissue. Thevapors can also cause severe eye and lungirritation and may cause tissue damage.The beaker and its contents get very hot,as well. Minimize risk by performing thisdemonstration under a fume hood or out-side, and use protective goggles, a faceshield, and gloves. Be sure students stay atleast 1–2 m away from the beaker at alltimes. Handle the chunk of carbon pro-duced in the experiment with tongs, as itwill still be coated with sulfuric acid.

What to Do

1. Find a suitable location for this demon-stration. Make sure there is enoughroom for the students to stand 1–2 mfrom the reaction and still see clearly.

2. Place 30 mL of sugar in the beaker.

3. Slowly add 5–10 mL of sulfuric acid tothe sugar.

4. Stand back and watch! As clouds ofsteam and smoke are produced, stu-dents should observe carbon “growing”out of the beaker.

Explanation

When the sulfuric acid (H2SO4) combinedwith the sugar (C12H22O11), a chemicalchange took place. As the sugar was dehy-drated, energy was released in the form ofheat. Water vapor and sulfur dioxide es-caped as gases. The black substance left inthe beaker is carbon.

Discussion

Use the following questions as a guide toencourage class discussion:

• Does the substance remaining in thebeaker resemble any substance you’veseen before? (The substance resemblescoal.) Explain that coal is a form of carbon.

• What ingredient used in the demonstra-tion may have contained carbon? (Sugar)How do you know? (All living things con-tain carbon. Sugar is the byproduct of a liv-ing thing, a plant.)

• Did you observe a chemical or physicalchange? (Chemical) How do you know?(A new substance was formed.)

MATERIALS

• 100 mL beaker• 30 mL of sugar• 5–10 mL of sulfuric acid• a face shield• chemical-resistant gloves• tongs

Brian BurnightBig Bear Middle SchoolBig Bear Lake, California

TEACHER PREP

CONCEPT LEVEL

CLEAN UP

E A S Y H A R D

Lab Ratings

Waiter, There’s Carbon in My Sugar Bowl STUDENT WORKSHEET

LAB

20

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How do scientists know what elements make up theouter layers of the sun? After all, they can’t justscoop up a bucketful of sun and bring it back to thelaboratories on Earth for analysis. There must besome indirect way of determining the compositionof the sun’s outer layers. Scientists can tell what el-ements make up the outer layers of the sun by look-ing at sunlight through a device called aspectroscope. Like a prism, a spectroscope breaks uplight into different wavelengths.

In fact, every element has its own “light finger-print,” which means that each element gives off dis-tinctively colored bands of light! Shortly, you’ll havea chance to correlate bands of light with the el-ements because Agent Spectra is about to send you a secret message made of light! To help you crackthe code, Agent Spectra sent you the decoder cardshown at right. Now all you need to do is constructa spectroscope and wait for the light signals. As soonas you identify the elements, you will read and inter-pret Agent Spectra’s secret message!

The Chemical Side of Light

ObjectiveDetermine the chemical composition of various light sources,and crack the code!

Construct a Spectroscope1. Trace two circles onto the card using the end of the tube.

2. Cut the two circles slightly larger than the tube’s diameter.

3. Mark a 2 � 2 cm square in the center of one circle.

4. Cut the square from the circle so you have a square hole.

5. Tape the diffraction grating over the hole.

6. Tape the circle with the diffraction grating over one openingof the cardboard tube so that light must passthrough the grating to enter the tube.

7. Bring the other circle to your teacher, whowill cut a thin slit in its center.

8. Place the circle with the slit against the openend of the tube. Hold the circle in place asyou look at a light source through the otherend of the spectroscope.

MATERIALS

• cardboard tube• index card• scissors• metric ruler• diffraction grating• masking tape• set of crayons or col-

ored pencils• light source

Substance Code

Na for want of a

K the

Hg was lost

Ne horse

Sr nail

Cu shoe

H � C rider

Decoder Card

Copyright © by Holt, Rinehart and Winston. All rights reserved.Copyright © by Holt, Rinehart and Winston. All rights reserved.


Name Class Date

Reaction to StressQuick Lab DATASHEET FOR QUICK LAB

BackgroundThe graph below illustrates changes that occur in the membrane potential of aneuron during an action potential. Use the graph to answer the followingquestions. Refer to Figure 3 as needed.

Analysis1. Determine about how long an action potential lasts.

2. State whether voltage-gated sodium, chanels are open or closed at point A.

3. State whether voltage-gated potassium channels are open or closed atpoint B.

4. Critical Thinking Recognizing Relationships What causes the menberneotential to become less negative at point A?

5. Critical Thinking Recognizing Relationships What causes the membranepotential to become more negative at point B?


Answer here.

Answer here.

Answer here.

Answer here.

Answer here.

Using Scientific Methods

For a preview of available worksheets covering math, science, and reading skills, see pages T26–T33. All of these resources are also on the One-Stop Planner®.

GENERAL

GENERALGENERAL

GENERAL

GENERAL

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GENERAL

SPECIAL NEEDS

SPECIAL NEEDS GENERAL

GENERAL

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SAMPLE

SAMPLE SAMPLE

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DATASHEETS FORCHAPTER LABS

Teacher’s NotesTIME REQUIRED

One 45-minute class period.

RATINGTeacher Prep–3Student Set-Up–2Concept Level–2Clean Up–2

MATERIALS

The materials listed on the student page are enough for a group of 4–5 students.Large, dried beans of any kind will work well in this exercise.

SAFETY CAUTION

Remind students to review all safety cautions and icons before beginning this labactivity.

Using Scientific MethodsSkills Practice Lab DATASHEET FOR CHAPTER LAB


1 2 3 4Easy Hard

Jason MarshMontevideo High

and Country School

SAMPLE

DATASHEETS FORLABBOOK

Teacher’s NotesTIME REQUIRED

One 45-minute class period.

Does It All Add Up?Skills Practice Lab DATASHEET FOR LABBOOK LAB


Jason MarshMontevideo High

SAMPLE

Chapter Enrichment

333E Chapter 12 • The Periodic Table

This Chapter Enrichment provides relevant and

interesting information to expand and enhance

your presentation of the chapter material.

Arranging the ElementsBefore the Periodic Table• Elements such as gold, sil-

ver, tin, copper, lead, and mercury have been known for thousands of years.

• The first modern discovery of an element was in 1669 when German alchemist Hennig Brand discovered phosphorus by precipitating it out of urine.

• Sixty-three elements had been discovered by 1869. As more elements were discovered, scientists recog-nized similarities and patterns in the properties of elements, and some scientists proposed classification schemes.

• In 1817, Johann Döbereiner (1780–1849) realized that calcium, strontium, and barium have similar proper-ties and that the atomic weight of strontium is about halfway between those of the other two elements.

Is That a Fact!◆ The first comprehensive arrangement of the elements

showing the periodicity of chemical and physical properties was published in 1862 by French geologist A. E. Beguyer de Chancourtois. De Chancourtois posi-tioned the elements on a cylinder in order of increas-ing atomic weight. When he arranged the elements so that there were 16 on the cylinder per turn, he noted that closely related elements lined up vertically.

The Law of Triads• In 1829, after discovering the triad chlo-

rine, bromine, and iodine and the triad lithium, sodium, and potassium, Döbereiner proposed his law of triads: In nature, there are triads of elements in which the middle element has an atomic weight that is the average of the atomic weights of the other two elements in the triad.

• Between 1829 and 1858, several scientists worked on the idea of triads. They discovered that the chemical relationship extended beyond groups of three. Fluorine was added to the halogen group; oxygen, sulfur, sele-nium, and tellurium were grouped into a family; and nitrogen, phosphorus, arsenic, antimony, and bismuth were grouped into a family.

The Law of Octaves• English chemist John Newlands (1837–1898) noticed

that several pairs of similar elements were separatedin atomic weight by some multiple of 8. In 1864, Newlands proposed his law of octaves: Elements whose atomic weights differ by some multiple of 8 have similar properties.

The Father of the Periodic Table?• Two chemists, a German named Lothar Meyer (1830–1895)

and a Russian named Dmitri Mendeleev (1834–1907), produced—completely independently of each other—nearly identical tables of the elements at almost the same time.

• Unfortunately for Meyer, Mendeleev’s table was published in 1869, a year before Meyer’s table, and Mendeleev received credit for the first modern periodic table of the elements.

Is That a Fact!◆ Mendeleev’s (and Meyer’s) table was a pioneering

development because it allowed scientists to predict the existence of elements that had not yet been dis-covered. Most scientists were skeptical at first. But then gallium was discovered in 1875 and was found to closely match Mendeleev’s predictions.

12

Grouping the ElementsWhat Goes Where?• Mendeleev’s table showed that the elements could be

grouped into periods, but it didn’t explain why. As themodern periodic table took shape, scientists realizedthat the underlying order was based on atomic struc-ture, namely, the number of protons in each atom.

• The known elements fall into three main categories,or classes: metals, metalloids (semiconductors), andnonmetals.

The Noble Gases• One of the most important additions to the periodic

table was the addition of the noble gases. Englishphysicists John William Strutt, Lord Rayleigh(1842–1919), and William Ramsay (1852–1916)discovered argon in 1894.

• In 1895, Ramsay discovered that helium exists onEarth. Then, in 1898 Ramsay (and his assistant,Morris W. Travers) discovered three more noblegases—neon, krypton, and xenon.

• Radon was discovered by German scientist FriedrichErnst Dorn (1848–1916) in 1900.

Is That a Fact!◆ Argon makes up about 1% of Earth’s atmosphere, but

argon remained completely undetected until 1894because it is unreactive under normal conditions.

The Modern Periodic Table• In the early 1940s, Glenn Seaborg and his team worked

on the Manhattan Project, the United States’s secreteffort to make the atomic bomb. Seaborg and his col-leagues discovered the element plutonium in 1940.

• In the 1940s and 1950s, Seaborg’s team synthesizedand identified all transuranic elements that haveatomic numbers 94 to 102. Seaborg also rearrangedthe periodic table by placing the actinide series belowthe lanthanide series. This change was the last majorchange to the modern periodic table.

Transuranic Elements• Elements whose atomic numbers are greater than 92,

known as transuranic elements, have been made in labo-ratories by bombarding heavy elements with neutronsor other subatomic particles. Plutonium (atomic num-ber 94) occurs in small amounts in nature. Scientistscontinue to make heavier transuranic elements, so theperiodic table continues to change.

• All transuranic elements are radioactive, and someexist for only short amounts of time before theydecay into other, lighter elements.

For background information about teaching strategies and

issues, refer to the Professional Reference for Teachers.

Topic: Periodic TableSciLinks code: HSM1125

Topic: MetalsSciLinks code: HSM0947

Topic: Alkali MetalsSciLinks code: HSM0043

Topic: Halogens and Noble GasesSciLinks code: HSM0711

Topic: MetalloidsSciLinks code: HSM0946

Topic: NonmetalsSciLinks code: HSM1043

Visit www.scilinks.org and enter the SciLinks code formore information about the topic listed.

SciLinks is maintained by the National Science Teachers Associationto provide you and your students with interesting, up-to-date links thatwill enrich your classroom presentation of the chapter.

Developed and maintained by theNational Science Teachers Association

Chapter 12 • Chapter Enrichment 333F

Standards Correlations

OverviewTell students that this chapterwill help them learn about theperiodic table of the elements.The chapter describes some ofthe history of the developmentof the table and describes char-acteristics of each group ofelements on the table.

Assessing PriorKnowledgeStudents should be familiarwith the following topics:

• chemical and physicalprop erties

• atomic number

IdentifyingMisconceptionsAs students learn the material inthis chapter, some of them maybe confused about how to tellwhether an element is a metal,a metalloid, or a nonmetal.Remind students as they studythe chapter that the zigzag lineshown on most periodic tablesis a helpful tool but that theelements are classified based ontheir properties.

National Science Education Standards

The following codes indicate the National Science EducationStandards that correlate to this chapter. The full text of thestandards is at the front of the book.

Chapter OpenerUCP 1, 2; SAI 1; ST 2; SPSP 5; HNS 1, 3

Section 1 Arranging the ElementsUCP 1; SAI 2; SPSP 5; HNS 1, 2, 3; PS 1b

Section 2 Grouping the ElementsST 2; PS 1b, 3e

Chapter LabUCP 1; SAI 1, 2

Chapter ReviewPS 1b

Science in ActionUCP 5; HNS 1, 3

12

334 Chapter 12 • The Periodic Table

PRE-READINGPRE-READING

The Periodic Table

About the

You already know or have heard aboutel ements on the periodic table, such asoxygen, carbon, and neon. Neon gas was discovered in 1898. In 1902, a French engi-neer, chemist, and inventor named GeorgesClaude made the fi rst neon lamp. In 1910,Claude made the fi rst neon sign, and in 1923,he introduced neon signs to the United States.Now, artists such as Eric Ehlenberger useglass and neon to create interesting works ofart, such as these neon jellyfi sh.

Three-Panel Flip ChartBefore you read the chapter,create the FoldNote entitled

“Three-Panel Flip Chart” described in theStudy Skills section of the Appendix.Label the flaps of the three-panel flipchart with “Metal,” “Nonmetal,” and“Metalloid.” As you read the chapter,write informationyou learn about eachcategory under theappropriate flap.

SECTION

Elements are organized onthe periodic table accordingto their properties.

12

1 Arranging the Elements. . . . . . 336

2 Grouping the Elements . . . . . . 344

START-UPPlacement PatternIn this activity, you will identify the pattern your teacher used to create a new classroom seating arrangement.

Procedure1. Draw a seating chart for the new classroom

arrangement that your teacher gave to you. Write the name of each of your classmates in the place on the chart that corresponds to his or her seat.

2. Write information about yourself, such as your name, date of birth, hair color, and height, in the space that represents you on the chart.

3. Gather the same information about the people near you, and write it in the spaces on the chart.

Analysis1. From the information you gathered, identify a

pattern that might explain the order of people in the chart. Collect more information if needed.

2. Test your pattern by gathering information from a person you did not talk to before.

3. If the new information does not support your pattern, reanalyze your data and collect more information to determine another pattern.

Chapter 12 • The Periodic Table 335

START-UPSTART-UP vv

Teacher’s Notes: To do this activity, you will need to make a seating chart before the class period. Possible organizational ideas for the arrangement include placing students by birth date, by height, or alpha-betically by their first names. This activity can be repeated by using different patterns, includ-ing patterns that are periodic.

Answers

1. Students should be able to describe the new seating pattern and, using the information they collected, explain how they arrived at their result.

3. Some students may have diffi-culty determining the new seating pattern. Encourage other students to assist them in analyzing the data and finding the pattern.

Would YouBelieve . . . ?Suppose someone told you that the small animalshown above—a yellow-spotted rock hyrax—isgenetically related to an elephant. Impossible, you say? But it’s true! Even though this animallooks more like a rabbit or a rodent, scientistshave determined through DNA studies that theclosest relatives of the hyrax are aardvarks, seacows, and elephants. Biologists have uncoveredsimilar genetic links between other seemingly different species.

Scientists have also discovered that many different-looking elements, like those shown atright, actually have common properties. For almost150 years, scientists have organized elements byobserving the similarities (both obvious and notso obvious) between them. One scientist in particular—a Russian named Dmitri Mendeleev(MEN duh LAY uhf )—organized the known elementsin such a way that a repeating pattern emerged.Mendeleev actually used this patternto predict the properties of elementsthat had not even been discovered! Hismethod of organization becameknown as the periodic table.

The modern periodic table isarranged somewhat differently thanMendeleev’s, but it is still a useful toolfor organizing the known elements andpredicting the properties of elementsstill unknown. Read on to learn aboutthe development of this remarkabletable and the patterns it reveals.

The Periodic Table CHAPTER STARTER

Although solid iodine and liquid bromine havevery different appearances, they have similarchemical properties.


Chapter Starter TransparencyUse this transparency to help students begin thinking about classifying items based on shared properties.

CHAPTER RESOURCESTechnology

Transparencies • Chapter Starter Transparency

Student Edition on CD-ROM

Guided Reading Audio CD • English or Spanish

Classroom Videos • Brain Food Video Quiz

Workbooks

Science Puzzlers, Twisters & Teasers • The Periodic Table g

READINGSKILLS

READING STRATEGY

Arranging the ElementsSuppose you went to the video store and all the videos were mixed together. How could you tell the comedies from the action movies? If the videos were not arranged in a pattern, you wouldn’t know what kind of movie you had chosen!

Scientists in the early 1860s had a similar problem. At thattime, scientists knew some of the properties of more than 60elements. However, no one had organized the el ements accord-ing to these properties. Organizing the elements according totheir properties would help scientists understand how elementsinteract with each other.

Discovering a PatternDmitri Mendeleev (duh MEE tree MEN duh LAY uhf), a Russianchemist, discovered a pattern to the elements in 1869. First,he wrote the names and properties of the elements on cards.Then, he arranged his cards, as shown in Figure 1, by differentproperties, such as density, appearance, and melting point. Aftermuch thought, he arranged the elements in order of increasingatomic mass. When he did so, a pattern appeared.

✓✓Reading Check How had Mendeleev arranged elements when he noticed a pattern? (See the Appendix for answers to Reading Checks.)

1

Figure 1 By playing “chemical solitaire” on long train rides, Mendeleev organized the elements according to their properties.

What You Will Learn

Describe how Mendeleev arrangedelements in the first periodic table.Explain how elements are arrangedin the modern periodic table.Compare metals, nonmetals, andmetalloids based on their propertiesand on their location in the periodictable.Describe the difference between aperiod and a group.

Vocabularyperiodic periodperiodic law group

Mnemonics As you read thissection, create a mnemonic deviceto help you remember the differencebetween periods and groups.

OverviewThis section gives a short historyof the periodic table. Studentslearn about the modern periodictable and are shown how tointerpret it, and they learn howcharacteristics of elements led toa logical way of grouping theelements.

BellringerAsk students to think of all ofthe ways a deck of cards couldbe laid out so that the cardsform some sort of identifiablepattern. Have students writedown as many patterns asthey can.

Demonstration --------------gGrouping Ask three volunteersto stand at the front of the class.Put two of them together, andask the third to step off to theside for a moment. Ask the classto list characteristics that thetwo students share. List studentresponses on the board.

Now, separate the two students,and ask the third student tostand next to one of the otherstudents. Repeat the exercise.Compare the two lists of charac-teristics. Discuss with the classthe similarities and differencesin the lists. l Visual/Logical Answer to Reading Check

Mendeleev had arranged elements based onincreasing atomic mass.

1

CHAPTER RESOURCES

Chapter Resource File

CRF • Lesson Plan• Directed Reading Ab• Directed Reading Bs

Technology

Transparencies• Bellringer

Workbooks

Interactive Textbook Struggling Readers Struggling Readers


Periodic Properties of the ElementsMendeleev saw that when the elements were arranged in order of increasing atomic mass, those that had similar properties occurred in a repeating pattern. That is, the pattern was peri-odic. Periodic means “happening at regular intervals.” The days of the week are periodic. They repeat in the same order every 7 days. Similarly, Mendeleev found that the elements’ prop-erties followed a pattern that repeated every seven elements. His table became known as the periodic table of the elements.

Predicting Properties of Missing ElementsFigure 2 shows part of Mendeleev’s first try at arranging the elements. The question marks show gaps in the pattern. Mendeleev predicted that elements yet to be found would fill these gaps. He used the pattern he found to predict their properties. Table 1 compares his predictions for one missing element—germanium—with its actual properties. By 1886, all of the gaps had been filled. His predictions were right.

Changing the ArrangementA few elements’ properties did not fit the pattern in Mendeleev’s table. Mendeleev thought that more-accurate atomic masses would fix these flaws in his table. But new atomic mass measurements showed that the masses he had used were cor-rect. In 1914, Henry Moseley (MOHZ lee), a British scientist, determined the number of protons—the atomic number—in an atom. All elements fit the pattern in Mendeleev’s periodic table when they were arranged by atomic number.

Look at the periodic table on the next two pages. All of the more than 30 el ements discovered since 1914 follow the periodic law. The periodic law states that the repeating chemical and physical properties of elements change periodically with the elements’ atomic numbers.

✓Reading Check What property is used to arrange elements in the periodic table?

Figure 2 Mendeleev used question marks to mark some elements that he thought would be found later.

Table 1 Properties of GermaniumMendeleev’spredictions (1869)

Actualproperties

Atomic mass 70 72.6

Density* 5.5 g/cm3 5.3 g/cm3

Appearance dark gray metal gray metal

Melting point* high melting point 937°C

* at room temperature and pressure

periodic describes something that occurs or repeats at regular intervals

periodic law the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements

SKILLHidden Help You may be asked to

memorize some of the chemi-cal symbols. A story or poem that uses the symbols might be helpful. In your science journal, write a short story, poem, or just a few sentences in which the words correspond to and bring to mind the chemical symbols of the first 20 elements.

Section 1 • Arranging the Elements 337

vv---------------------------------------------------g

Element Sampling Obtain sam-ples of several elements that have visibly different properties and that can be displayed safely. Suggestions include:

• sulfur (in powder form)

• helium (in a clear balloon)

• iron (nails)

• aluminum (foil or gutter nails)

• nitrogen (a clear balloon filled with air)

• carbon (charcoal briquettes: some crushed and some whole)

• copper (electrical wire)

• silver (necklace or silver-plated tableware)

You might want to set up sta-tions throughout the room and include several samples at each station. Ask students if they can identify any of the samples, and discuss why they have made a particular identification. Help students identify and label all of the elements. Then, ask students to identify observed characteris-tics, such as color, physical state (solid, liquid, or gas), and luster (shininess or glossiness), for each element. List on the board all the characteristics for each element. Give hints about char-acteristics that students might miss. l Visual

Answer to Reading Check

atomic number

h ----------------------------g

Reviewing Atoms Have students review information that they have learned about atoms by using the following terms to make a concept map: atom, proton, neutron, electron, atomic number, and atomic mass. l Visual/Logical

Is That a Fact!In the late 1800s, scientists began study-ing the color spectra that elements pro-duced when heated. There are patterns within the spectra, and all of the pat-terns are different—no two elements have the same spectrum.

140.1

232.0

140.9

231.0

144.2

238.0

(145)

(237)

150.4

(244)

6.9

23.0

39.1

85.5

132.9

9.0

24.3

40.1

87.6

137.3

(226)

45.0

88.9

138.9

(227)

47.9

91.2

178.5

(261)

50.9

92.9

180.9

(262)

52.0

95.9

183.8

(266)

54.9

(98)

186.2

(264)

55.8

101.1

190.2

(277)

58.9

102.9

192.2

(268)

1.0

Praseodymium

Rutherfordium

Molybdenum

Lithium

Sodium

Potassium

Rubidium

Cesium

Cerium

Thorium Protactinium

Neodymium

Uranium

Promethium

Neptunium

Samarium

Plutonium

Beryllium

Magnesium

Calcium

Strontium

Barium

Radium

Scandium

Yttrium

Lanthanum

Actinium

Titanium

Zirconium

Hafnium

Vanadium

Niobium

Tantalum

Dubnium

Chromium

Tungsten

Seaborgium

Manganese

Technetium

Rhenium

Bohrium

Iron

Ruthenium

Osmium

Hassium

Cobalt

Rhodium

Iridium

Meitnerium

Hydrogen

Li

V

Na

K

Rb

Cs

Fr

Be

Mg

Ca

Sr

Ba

Ra

Sc

Y

La

Ac

Ti

Zr

H f

Rf

Nb

Ta

Db

Cr

Mo

W

Sg

Mn

Re

Bh

IrOs

Ce

Th

Pr

Pa

Nd

U

Pm

Np

Sm

Pu

Fe

Ru

Hs

Co

Rh

Mt

H

Tc

3

11

19

37

55

87

58

90

59

91

60

92

61

93

62

94

4

12

20

38

56

88

21

39

57

89

22

40

72

104

23

41

73

105

24

42

74

106

25

43

75

107

26

44

76 77

108

27

45

109

1

Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Group 9

Group 1 Group 2

Period 1

Period 2

Period 3

Period 4

Period 5

Period 6

Period 7

Lanthanides

Background

Metals

Metalloids

Nonmetals

Chemical symbol

Solid

Liquid

Gas

6

CThe color of the chemical sym-bol indicates the physical state at room temperature. Carbon is a solid.

The background color indicates the type of element. Carbon is a nonmetal.

These elements are placed below the table to allow the table to be narrower.

A column of elements is called a group or family.

Atomic number

Chemical symbol

Element name

Atomic mass

A row of elements is called a period.

Values in parentheses are the mass numbers of those radioactive elements’ most stable or most common isotopes.

Periodic Table of the ElementsEach square on the table includes an element’s name, chemical symbol, atomic number, and atomic mass.

READINGSTRATEGY -----------------g

Discussion Help studentsrecognize the layout pattern forthe periodic table of the elements.Have them count across the table,group by group, to see that thereare a total of 18 groups. Also, havestudents count the 7 periods. Dis-cuss the triads that Döbereinerfound (see the Chapter Enrich-ment pages at the beginning ofthis chapter), the expanded triads,and the noble gases. Emphasizethat the lanthanides and actinidesare parts of periods 6 and 7 andare not periods by themselves.l Visual

CHAPTER RESOURCESTechnology

Transparencies• P109 The Periodic Table of the Elements

SUPPORT FOR

English LanguageLearnersThe Periodic Table Studentsmay have diffi culty readingsuch a complex table with somany symbols. Use the tablein the book to help studentsas a class recognize the layoutpattern for the periodic tableof elements. Model count-ing across the table groupby group. Ask students tocount across and tell you howmany groups there are. (18)Show that a row of elementsis called a period, and havestudents count the seven pe-riods. Point out that the lasttwo rows, the lanthanides andactinides, are parts of periods6 and 7 and are not periodsby themselves.l Visual/Logical


152.0

(243)

157.2

(247)

158.9

(247)

162.5

(251)

164.9

(252)

167.3

(257)

168.9

(258)

173.0

(259)

175.0

(262)

58.7 63.5 65.4 69.7 72.6 74.9 79.0 79.9 83.8

27.0 28.1 31.0 32.1 35.5 39.9

10.8 12.0 14.0 16.0 19.0 20.2

4.0

106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3

195.1

(281) (272)

197.0 200.6 204.4 207.2 209.0 (209) (210) (222)

(285) (289) (288)(284)

Europium

Americium

Gadolinium

Curium

Terbium

Berkelium

Dysprosium

Californium

Holmium

Einsteinium

Erbium

Fermium

Thulium

Mendelevium

Ytterbium

Nobelium

Lutetium

Lawrencium

Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton

Aluminum Silicon Phosphorus Sulfur Chlorine Argon

Boron Carbon Nitrogen Oxygen Fluorine Neon

Helium

Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon

Darmstadtium Unununium

Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon

Ununbium Ununquadium UnunpentiumUnuntrium

Eu

Am

Gd

Cm

Tb

Bk

Dy

Cf

Pd Ag Cd In Sn Sb Te I Xe

Pt

Ds Uuu

Au Hg Tl Pb Bi Po At Rn

Ho

Es

Er

Fm

Tm

Md

Yb

No

Lu

Lr

Ni Cu Zn Ga Ge As Se Br Kr

Al Si P S Cl Ar

B C N O F Ne

He

Uub Uuq UupUut

28 29 30 31 32 33 34 35 36

13 14 15 16 17 18

5 6 7 8 9 10

2

46 47 48 49 50 51 52 53 54

78 79 80 81 82 83 84 85 86

110 111

63

95

64

96

65

97

66

98

67

99

68

100

69

101

70

102

71

103

112 114 115113

Group 13 Group 14 Group 15 Group 16 Group 17

Group 18

Group 10 Group 11 Group 12

The discovery of elements113, 114, and 115 has beenreported but not confirmed.

This zigzag line reminds you where the metals, nonmetals, and metalloids are.

The names and three-letter symbols of elements are temporary. They are based on the atomic numbers of the elements. Official names and symbols will be approved by an international committee of scientists.

Topic: Periodic TableGo To: go.hrw.comKeyword: HN0 PERIODICVisit the HRW Web site for updates on the periodic table.

vv--------------------------------------a

Looking for Gaps Have stu-dents consider the progressionof atomic mass across the peri-odic table, where atoms differ innumber by one proton. Ask stu-dents to consider how scientistscan be sure that there are noundiscovered elements betweenhydrogen and uranium.l Logical

Research -------------------------------------------g

PORTFOLIO

What’s New? Scientistsare continually trying to

synthesize new elements. Askstudents to do some research tofind out if any new elementshave been synthesized since thisbook was published. Studentsmay present their findings in ashort report or poster. l Logical

CONNECTION toCONNECTION toHistory---------------------------------------------------g

Not Enough Elements Severalelements, such as gold, silver,copper, tin, and a few others,were known to ancient people.But there weren’t enoughknown el ements to show anypatterns or relationships. Itwasn’t until 1669, the year thatphosphorus was discovered, thatsteps toward creating the mod-ern per iodic table were taken.By 1869, a total of 63 elements(of the 92 that occur in nature)had been discovered. As moreelements were discovered, scien-tists began to see patterns ofproperties among the elementsand began to create classifica-tion schemes.

symbol], and type of element [color of thebackground]) “How many elements areliquid at room temperature?” (2) “Howmany elements are gas at room temper-ature?” (11) “How many elements are metals?” (88) “How many elements aremetalloids?” (6) “How many elementsare nonmetals?” (18) “How many groupsare the elements divided into?” (18) and“How many periods are the elementsdivided into?” (7) l Interpersonalcc

StrategiesStrategiesINCLUSIONINCLUSION

• Learning Disabled• Visually Impaired• Developmentally DelayedHelp students who have trouble under-standing or seeing the periodic tableby writing the questions below on theboard. Read each question aloud. Havestudents work in small groups to answereach one. “What information does eachsquare on the periodic table show?”(atomic number, chemical symbol, elementname, atomic mass, state [color of the


The Periodic Table and Classes of ElementsAt first glance, you might think studying the periodic table is like trying to explore a thick jungle without a guide—you can easily get lost! However, the table itself contains a lot of information that will help you along the way.

Elements are classified as metals, non metals, and metal-loids, according to their properties. The number of electrons in the outer energy level of an atom is one characteristic that helps determine which category an element belongs in. The zigzag line on the periodic table can help you recognize which elements are metals, which are nonmetals, and which are metalloids.

MetalsMost elements are metals. Metals are found to the left of the zigzag line on the periodic table. Atoms of most metals have few electrons in their outer energy level. Most metals are solid at room temperature. Mercury, however, is a liquid at room temperature. Some additional information on properties shared by most metals is shown in Figure 3.

✓Reading Check What are four properties shared by most metals?

Conduction Connection

1. Fill a plastic-foam cup with hot water.

2. Stand a piece of copper wire and a graphite lead from a mechanical pencil in the water.

3. After 1 min, touch the top of each object. Record your observations.

4. Which material conducted thermal energy the best? Why?

Properties of MetalsFigure 3

Metals tend to be shiny.You can see a reflection in a mirror because light reflects off the shiny sur-face of a thin layer of silver behind the glass.

Most metals are malleable,which means that they can be flattened with a hammer and will not shatter. Aluminum is flat-tened into sheets to make cans and foil.

Most metals are ductile, whichmeans that they can be drawn into thin wires. All metals are good con ductors of electric current. The wires in the elec-trical devices in your home are made of copper.

Most metals are good conductors of thermal energy. This iron griddle con-ducts thermal energy from a stove top to cook your favoritefoods.


M A T E R I A L S FOR EACH STUDENT

• cup, plastic-foam• graphite, mechanical pencil lead• water, hot• wire, copper, bare, 25 cm long

Safety Caution: Remind stu-dents to review all safety cau-tions and icons before beginning this lab activity.

Teacher’s Notes: The wire should be approximately the same thickness and length as the pencil lead. Test the pro-cedure; adjust the time if necessary.

Answer

4. The wire conducted thermal energy better than the pencil lead did. The wire is made of the metal copper; pencil lead is made of graphite, a form of the nonmetal carbon. Metals conduct thermal energy better than nonmetals do.


Most metals are solid at room tem-perature, ductile, malleable, and shiny. In addition, they are good conductors of electric current and thermal energy.

vv------------------------------------------b

Element Game Make a memory game by using two sets of flip pages. Select 24 elements. Have students write descriptions of these el ements on one set of flip pages and place images of items made from those elements on the second set of flip pages. The element’s name and symbol should be on the back of each page. Have students try to guess the element from its descrip-tion or its picture. Or have students match the pictures with the descriptions. l Visual ee

Is That a Fact!Mercury is the only metal that is liquid at room temperature. It was not thought to be a metal until it was frozen in 1759. The metal cesium is almost a liquid metal. It has a melting point of 28.4°C, so on a hot day, cesium metal would melt into a puddle.

NonmetalsNonmetals are found to the right of the zigzag line on the periodic table. Atoms of most nonmetals have an almost complete set of electrons in their outer level. Atoms of the elements in Group 18, the noble gases, have a complete set of electrons. More than half of the nonmetals are gases at room temperature. Many prop erties of nonmetals are the opposite of the properties of metals, as shown in Figure 4.

MetalloidsMetalloids, also called semiconductors, are the elements that border the zigzag line on the periodic table. Atoms of metal-loids have about half of a complete set of electrons in their outer energy level. Metalloids have some properties of metals and some properties of nonmetals, as shown in Figure 5.

Properties of MetalloidsFigure 5

PercentagesElements are classified as metals, nonmetals, and met-alloids. Use the periodic table to determine the percentage of elements in each of the three categories.

Properties of NonmetalsFigure 4

Nonmetals are poor conductors of thermal energy and electric current. If the gap in a spark plug is too wide, the nonmetals nitrogen and oxygen in the air will stop the spark and a car’s engine will not run.

Nonmetals are not malleable or ductile. In fact, solid non-metals, such as carbon in the graphite of the pencil lead, are brittle and will break or shat-ter when hit with a hammer.

Sulfur, like most non-metals, is not shiny.

Tellurium is shiny, but it is brittle and can easily be smashed into a powder.

Boron is almost as hardas diamond, but it is also very brittle. At high tem-peratures, it is a good conductorof electric current.


CONNECTION toCONNECTION toReal World -----------------------------------g

Wiring Homes built between 1965 and 1973 may contain alu-minum wiring, which can be very dangerous. This type of wiring has conductors made of aluminum that may corrode at any connection. Corrosion causes increased electrical resis-tance, which may cause the wire to overheat and start a fire. By 1973, manufacturers had corrected the corrosion problem, so aluminum wiring used after 1973 is much safer. To be safe, people whose homes were wired between 1965 and 1973 should check the wiring and replace it if necessary.

Answers to Math Practice

79% metals, 5% metalloids, and 16% nonmetals

vv--------------------------------------g

Elements Everywhere Havestudents check the ingredients of foods and other products in their homes and write down the ingredients that have famil-iar chemical names, such as sodium fluoride. In class, have students place self-adhesive notes containing product names on the corresponding elements on a wall-chart periodic table. l Visual

INTERNETINTERNET vvSequence Board --------------g

For an internet activity related to this chapter, have students goto go.hrw.com and type in the keyword HP5PRTW.

oNaming New Elements Scientists who claim to have made a new element propose a name for it. Names are reviewed and sug-gested by a committee of the International Union of Pure and Applied Chemistry (IUPAC). This committee is made up of sci-entists who are competing with each other to make new elements, so the naming process is sometimes difficult. Eventually, the IUPAC designates one official name, and most scientists then refer to the new element by this official name.

Is That a Fact!Metalloids are also called semiconductorsbecause they conduct electric current more easily than nonmetals do but less easily than metals do. The semiconduc-tors silicon and germanium are extremely important in your everyday life. These elements are used to create microproces-sors for computers.

VK Ti Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Ti Ge BrTitanium

22 32 35

Decoding the Periodic TableThe periodic table may seem to be in code. In a way, it is. Butthe colors and symbols will help you decode the table.

Each Element Is Identified by a Chemical SymbolEach square on the periodic table includes an element’s name,chemical symbol, atomic number, and atomic mass. The namesof the elements come from many sources. Some elements, suchas mendelevium, are named after scientists. Others, such ascalifornium, are named after places. Some element names varyby country. But the chemical symbols are the same worldwide.For most elements, the chemical symbol has one or two let-ters. The first letter is always capitalized. Any other letter isalways lowercase. The newest elements have temporary three-letter symbols.

Rows Are Called PeriodsEach horizontal row of elements (from left to right) on theperiodic table is called a period. Look at Period 4 in Figure 6. Thephysical and chemical properties of elements in a row follow arepeating, or periodic, pattern as you move across the period.Properties such as conductivity and reactivity change graduallyfrom left to right in each period.

Columns Are Called GroupsEach vertical column of elements (from top to bottom) on theperiodic table is called a group. Elements in the same groupoften have similar chemical and physical properties. For thisreason, a group is also called a family.

✓Reading Check Why is a group sometimes called a family?

Patterns of SymbolsDivide a sheet of paper intofour columns. Look at theelements whose atomicnumbers are 1 to 20 onthe periodic table. With aparent, find patterns thatdescribe the relationshipbetween the chemical sym-bols and names of elements.In each column, write all ofthe chemical symbols andnames that follow a singlepattern. At the top of eachcolumn, write a sentencedescribing the pattern.

Figure 6 As you move from left to right across a row,the elements become less metallic.

period in chemistry, a horizontalrow of elements in the periodic table

group a vertical column ofelements in the periodic table;elements in a group sharechemical properties

Elements at the left end ofa period, such as titanium,are very metallic.

Elements farther to theright, such as germanium,are less metallic.

Elements at the far-right endof a period, such as bromine,are nonmetallic.

Reteaching -------------------------------------bMalleable and Brittle Reinforcethe meanings of the terms mal-leable and brittle.

Safety Caution: Students shouldwear safety goggles when doingthis activity.

To demonstrate malleability, showstudents small pieces of lead, suchas fishing weights. Use a hammerto shape the lead. To demonstratebrittleness, use a hammer to strikea charcoal briquette wrapped inan old towel. l Visual

Quiz --------------------------------------------------------------------g

1. What does the periodic lawstate? (The chemical and physi-cal properties of elements areperiodic functions of the atomicnumbers of the elements.)

2. Which elements are in thesame group on the periodictable as oxygen is? (sulfur, sele-nium, tellurium, and polonium)

3. List five elements whose sym-bols don’t seem to come fromtheir English names. For exam-ple, Fe is iron. (Others includepotassium, K; sodium, Na; tung-sten, W; copper, Cu; silver, Ag;and gold, Au.)


Elements in a group often havesimilar chemical and physicalproperties.

Answer to School-to-Home Activity

• One column should include the following: hydro-gen, H; boron, B; carbon, C; nitrogen, N; oxygen,O; fluorine, F; phosphorus, P; and sulfur, S. Thechemical symbol for each of these elements isthe first letter of the name of the element.

• The second column should include the follow-ing: helium, He; lithium, Li; beryllium, Be; neon,Ne; aluminum, Al; silicon, Si; argon, Ar; andcalcium, Ca. The chemical symbol for eachof these elements is the first two letters ofthe name of the element.

• The third column should include the following:sodium, Na; and potassium, K. The chemicalsymbols for these elements do not seem tohave a direct connection to the names of theelements. (In fact, the symbols come from theLatin words natrium [sodium carbonate] andkalium [alkali].)

• The fourth column should include the followingelements: magnesium, Mg; and chlorine, Cl.The chemical symbol for each of these ele-ments consists of the first and third letters ofthe name of the element.


For a variety of links related to thischapter, go to www.scilinks.org

SummarySummary

Review

Using Key Terms

1. In your own words, write a definition for theterm periodic.

Understanding Key Ideas

2. Which of the following elements should be thebest conductor of electric current?

a. germaniumb. sulfurc. aluminumd. helium

3. Compare a period and a group on the periodictable.

4. What property did Mendeleev use to positionthe elements on the periodic table?

5. State the periodic law.

Critical Thinking

6. Identifying Relationships An atom that has117 protons in its nucleus has not yet beenmade. Once this atom is made, to which groupwill element 117 belong? Explain your answer.

7. Applying Concepts Are the properties ofsodium, Na, more like the properties of lithium,Li, or magnesium, Mg? Explain your answer.

Interpreting Graphics

8. The image below shows part of a periodic table.Compare the image below with the similar partof the periodic table in your book.

Topic: Periodic Table; MetalsSciLinks code: HSM1125; HSM0947

• Mendeleev developed the first periodictable by listing the elements in order ofincreasing atomic mass. He used his tableto predict that elements with certain prop-erties would be discovered later.

• Properties of elements repeat in a regular,or periodic, pattern.

• Moseley rearranged the elements in orderof increasing atomic number.

• The periodic law states that the repeat-ing chemical and physical propertiesof elements relate to and depend onelements’ atomic numbers.

• Elements in the peri-odic table are classifiedas metals, nonmetals, andmetalloids.

• Each element has a chemical symbol.

• A horizontal row of elements is called aperiod.

• Physical and chemical properties ofelements change across each period.

• A vertical column of elements is called agroup or family.

• Elements in a group usually have similarproperties.

AlternativeAssessment ---------------------------g

Element Report Photocopythe periodic table, and cut thesquares of the elements out ofthe copy. Fold each square inhalf, and put the squares into abox. Ask each student to selectthree squares and then write ashort report for each element.The report should include

• the full chemical name ofeach element

• identification of each elementas a metal, a metalloid, or anonmetal

• the order of the three elementsby increasing atomic mass

• identification of each element’sgroup and period

• any interesting facts aboutor important uses of eachelementl Logical

Answers to Section Review

1. Sample answer: Periodicmeans “happening in a regularrepeating pattern.”

2. c3. A period in the periodic

table is a horizontal row ofel ements. A group is a verticalcolumn of elements.

4. atomic mass5. The repeating chemical

and physical properties ofelements change periodicallywith the atomic numbers ofthe elements.

6. Group 17; Element 117 has117 protons. So, it would fallunder astatine in the periodictable.

7. lithium; Sodium and lithiumare in the same group, so theirproperties should be more alikethan the properties of sodiumand magnesium are.

8. The periodic table has thesame shape, atomic numbers,and chemical symbols. Thenames of the elements are in adifferent language (Japanese).

CHAPTER RESOURCES


• Section Quizg• Section Reviewg• Vocabulary and Section Summaryg• SciLinks Activityg• Datasheet for Quick Lab

CRF


READING STRATEGY

Grouping the ElementsYou probably know a family with several members who look a lot alike. The elements in a family or group in the periodic table often—but not always—have similar properties.

The properties of the elements in a group are similar becausethe atoms of the elements have the same number of electronsin their outer energy level. Atoms will often take, give, or shareelectrons with other atoms in order to have a complete set ofelectrons in their outer energy level. Elements whose atomsundergo such processes are called reactive and can combine toform compounds.

Group 1: Alkali Metals

Alkali metalsAlkali metals (AL kuh LIE MET uhlz) are elements inGroup 1 of the periodic table. They share physicaland chemical properties, as shown in Figure 1. Alkalimetals are the most reactive metals because their atomscan easily give away the one outer-level electron. Purealkali metals are often stored in oil. The oil keeps themfrom reacting with water and oxygen in the air. Alkalimetals are so reactive that in nature they are foundonly combined with other elements. Compoundsformed from alkali metals have many uses. For exam-ple, sodium chloride (table salt) is used to flavor yourfood. Potassium bromide is used in photography.

2

Group contains: metalsElectrons in the outer level: 1Reactivity: very reactiveOther shared properties: softness; color of silver;shininess; low density

Alkali metals react with water to form hydrogen gas.

Sodium Sodium Potassium

Alkali metals are soft enough to be cut with a knife.

Properties of Alkali MetalsFigure 1

What You Will Learn

Explain why elements in a groupoften have similar properties.Describe the properties of theel ements in the groups of theperiodic table.

Vocabularyalkali metalalkaline-earth metalhalogennoble gas

Paired Summarizing Read thissection silently. In pairs, take turnssummarizing the material. Stop to dis-cuss ideas that seem confusing.

Lithium

3Li

Sodium

11Na

Potassium

19K

Rubidium

37Rb

Cesium

55Cs

Francium

87Fr

Although the element hydro-gen appears

above the alkali metals on the periodic table, it is not considered a mem-ber of Group 1. It will be described separately at the end of this section.

OverviewStudents learn how properties ofelements are used to group theelements in the periodic table.Students also study the relation-ship that elements have to eachother and to the overall layoutof elements within the table.

BellringerAsk students the following ques-tions: “How do you know thata bird is a bird, that a kangaroois a kangaroo, and that a shark isa shark?” “What characteristicsof each animal help you to tellthe animals apart?” and “Howcan such an analysis of charac-teristics be applied to elements?”

Discussion ----------------------------------g

Universal Ingredients Handout several kinds of cookies. Askstudents to list the ingredients.(The goal is to list all of thethings from which you canmake cookies.) Show studentsthe list of ingredients for theentire universe—the periodictable of the elements. Discusswith students how theseelements combine to make allmatter. You can also remind stu-dents that the basic ingredientsof the atoms of the elementsare protons, neutrons, and electrons. l Visual

2

MISCONCEPTIONALERT

Explosive Alkali Metals? Textbooksoften show photos of an alkali metalreacting explosively with water and pro-ducing flames. Students should be awarethat the metal itself is not burning.When the metal reacts with water, oneof the products is hydrogen gas. Theenergy released during the reactionoften ignites the flammable hydrogen,thus producing flames. Also, the reactiv-ity of alkali metals with water varies.

CHAPTER RESOURCES


CRF • Lesson Plan• Directed Reading Ab• Directed Reading Bs

Technology

Transparencies• Bellringer• LINK TOLINK TO LIFE SCIENCELIFE SCIENCE L79 The Skeleton

Workbooks

Interactive Textbook Struggling Readers Struggling Readers


VSc

Y

Ti

Zr Nb

Cr

Mo

Mn Fe

Ru

Co

RhTc Pd Ag Cd

Ni Cu Zn

La

Ac

H f

Rf

Ta

Db

W

Sg

Re

Bh

IrOs

Hs Mt

Pt

Ds Uuu

Au Hg

Uub

21

39

57

89

22

40

72

104

23

41

73

105

24

42

74

106

25

43

75

107

26

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76 77

108

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28 29 30

46 47 48

78 79 80

110 111 112

Alkaline-earth metals (AL kuh LIEN UHRTH MET uhlz) areless reactive than alkali metals are. Atoms of alkaline-earthmetals have two outer-level electrons. It is more difficult foratoms to give two electrons than to give one when joiningwith other atoms. Group 2 elements and their compoundshave many uses. For example, magnesium can be mixedwith other metals to make low-density materials used inairplanes. And compounds of calcium are found in cement,chalk, and even you, as shown in Figure 2.

alkali metal one of theelements of Group 1 ofthe periodic table (lithium,sodium, potassium, rubid-ium, cesium, and francium)

alkaline-earth metal oneof the elements of Group 2of the periodic table (beryl-lium, magnesium, calcium,strontium, barium, andradium)

Figure 2 Calcium, analkaline-earth metal, isan important part of acompound that keepsyour bones and teethhealthy.

Group contains: metalsElectrons in the outer level: 1 or 2Reactivity: less reactive than alkaline-earth metalsOther shared properties: shininess; good conductors of thermal energyand electric current; higher densities and melting points than elements inGroups 1 and 2 (except for mercury)

Group contains: metalsElectrons in the outer level: 2Reactivity: very reactive but less reactive than alkali metalsOther shared properties: color of silver; higher densities thanalkali metals

Groups 3–12 do not have individual names. Instead, all of thesegroups are called transition metals. The atoms of transition metalsdo not give away their electrons as easily as atoms of the Group 1and Group 2 metals do. So, transition metals are less reactive thanalkali metals and alkaline-earth metals are.

✓Reading Check Why are alkali metals more reactive than transitionmetals are? (See the Appendix for answers to Reading Checks.)

Group 2: Alkaline-Earth Metals

Groups 3–12: Transition Metals

BerylliumBe

4

MagnesiumMg

12

CalciumCa20

StrontiumSr38

BariumBa56

RadiumRa

88


It is easier for atoms of alkali metals to losetheir outer electron than for atoms of transitionmetals to lose their outer electrons. Therefore,alkali metals are more reactive than transitionmetals.

StrategiesStrategiesINCLUSIONINCLUSION

• Gifted and TalentedSome students benefit from studying atopic in greater depth. Assign each ofthese students one of the groups fromthe periodic table. Ask students toresearch the elements in the group andto make a poster showing some uses forthose elements. l Visual/Logical

CulturalAwarenessCulturalAwareness g

From the Arabic The alkalimetals in Group 1, whichinclude potassium, got theirgroup name from Arabic.Hundreds of years ago, toisolate potassium compoundsfrom plant matter, peopleburned plants, dissolved theashes in water, and boiled offthe water in large pots. Thepowdery residue left behind,potassium carbonate, wascalled potash. The Arabicword for potash is al-qili.l Verbal

SUPPORT FOR

English LanguageLearnersElement Groups To help stu-dents become more familiarwith the various propertiesof the element groups, havepairs of students write thenames of each group on sepa-rate index cards. Ask studentsto place the groups in orderbased on various criteria (re-activity, number of elements,density, and so on). After youname each criteria, give thepairs time to order their cards,and, then, review the properorder and the reason for it asa class before moving to thenext criteria. Encourage stu-dents to ask questions abouteach order.l Verbal/Logical

Section 2 • Grouping the Elements 345

Lanthanum

57

Actinium

89

Lanthanides

Actinides

58 59 60 61 62 63 64 65 66 67 68 69 70 71

90 91 92 93 94 95 96 97 98 99 100 101 102 103

La

Ac

Ce

Th

Pr

Pa

Nd

U

Pm

Np

Sm

Pu

Eu

Am

Gd

Cm

Tb

Bk

Dy

Cf

Ho

Es

Er

Fm

Tm

Md

Yb

No

Lu

Lr

Properties of Transition MetalsThe properties of the transition metals vary widely, as shown in Figure 3. But, because these elements are metals, they share the properties of metals. Transition metals tend to be shiny and to conduct thermal energy and electric current well.

Lanthanides and ActinidesSome transition metals from Periods 6 and 7 appear in two rows at the bottom of the periodic table to keep the table from being too wide. The elements in each row tend to have similar properties. Elements in the first row follow lanthanum and are called lanthanides. The lanthanides are shiny, reactive metals. Some of these elements are used to make steel. An important use of a compound of one lanthanide element is shown in Figure 4.

Elements in the second row follow actinium and are calledactinides. All atoms of actinides are radioactive, or unstable. The atoms of a radioactive element can change into atoms of another element. Elements listed after plutonium, element 94, do not occur in nature. They are made in laboratories. Very small amounts of americ ium (AM uhr ISH ee uhm), element 95, are used in some smoke detectors.

✓Reading Check Are lanthanides and actinides transition metals?

Figure 4 Do you see red? The color red appears on a computer monitor because of a compound formed from europium that coats the back of the screen.

Mercury is used in thermometers. Unlike

the other transition metals, mercury is liquid at room temperature.

Many transition metals—but not all—are silver colored! This gold ring proves it!

Some transition metals, such as titanium in the artificial hip at right, are not very reactive. But others, such as iron, are reactive. The iron in the steel trowel on the left has reacted to form rust.


Titanium Titanium is a very light but very strong metal. Because of these properties, it is often used in structures such as airframes and jet engines. Titanium is highly resistant to corrosion and so can be used in very corrosive places, such as in salt water or in the human body.


Yes, lanthanides and actinides are transition metals.

MISCONCEPTIONALERT

Rare-Earth Elements On older periodic tables, the lan-thanides may be called the rare-earth elements, although this name is incorrect. Many of the lanthanides are more abundant than elements that are more well known are. The lanthanides are also often referred to as a series.Remind students that these elements (and the actinides) belong in the periodic table where their atomic numbers fit. However, the periodic table would be too wide to print or work with easily if these elements were printed in their proper place.

Is That a Fact!Mercury in Thermometers Mercury has been the liquid of choice for use in thermometers because as temperature changes, mercury expands and contracts at a nearly constant rate. That is, for every 1° change in temperature, mercury’s volume changes consistently.

In a meeting of the transition metals, mercury wished to speak to the entire group. But the group didn’t let mercury speak because they didn’t like to listen to heavy metal.

Group 13: Boron Group

The most common element from Group 13 is alumi-num. In fact, aluminum is the most abundant metalin Earth’s crust. Until the 1880s, however, aluminumwas considered a precious metal because the processused to make pure aluminum was very expensive.During the 1850s and 1860s, Emperor Napoleon III ofFrance used aluminum dinnerware because aluminumwas more valuable than gold.

Today, the process of making pure aluminum iseasier and less expensive than it was in the 1800s.Aluminum is now an important metal used in mak-ing aircraft parts. Aluminum is also used to makelightweight automobile parts, foil, cans, and siding.

Like the other elements in the boron group, alu-minum is reactive. Why can it be used in so manythings? A thin layer of aluminum oxide quickly formson aluminum’s surface when aluminum reacts withoxygen in the air. This layer prevents further reactionof the aluminum.

Group contains: one metalloid and five metalsElectrons in the outer level: 3Reactivity: reactiveOther shared properties: solids at room temperature

Figure 5 Diamond and soot have very different properties, yet both are natural forms of carbon.

Group 14: Carbon Group

The nonmetal carbon can be found uncombined innature, as shown in Figure 5. Carbon also forms a widevariety of compounds. Some of these compounds,such as proteins, fats, and carbohydrates, are neces-sary for living things on Earth.

The metalloids silicon and germanium, also inGroup 14, are used to make computer chips. Themetal tin is useful because it is not very reactive. Forexample, a tin can is really made of steel coated withtin. Because the tin is less reactive than the steel is,the tin keeps the iron in the steel from rusting.

✓✓Reading Check What metalloids from Group 14 are used to make computer chips?

RecyclingAluminum

Aluminum recycling is a very successful program. In your science journal, write a one-page report that describes how aluminum is processed from its ore. In your report, identify the ore and compare the energy needed to extract aluminum from the ore with the energy needed to process recycled aluminum.

WRITINGSKILL

Group contains: one nonmetal, two metalloids, and three metalsElectrons in the outer level: 4Reactivity: varies among the elementsOther shared properties: solids at room temperature

Indium

49In

Thallium

81Tl

Ununtrium

113Uut

Gallium

31Ga

Aluminum

13Al

Boron

5B

Tin

50Sn

Lead

82Pb

Ununquadium

114Uuq

Germanium

32Ge

Silicon

14Si

Carbon

6C

Diamond is the hardest ma terialknown. It is used as a jewel and on cutting tools, such as saws, drills, and files.

Soot is formed from burning oil, coal, and wood and is used as a pigment in paints and crayons.

CONNECTIONCONNECTION vvMath ---------------------------------------------------------------------------g

Relative Masses The atomicmasses of helium and carbon areapproximately 4 and 12, respec-tively. Ask students the follow-ing questions: “How manyhelium atoms would togetherhave about the same mass asone carbon atom? How manyhelium atoms would togetherhave the mass of one siliconatom?” (Three helium atomstogether have the same mass asone carbon atom, and seven heliumatoms together have the same massas one silicon atom.) l Logical

CONNECTION toCONNECTION toHistory --------------------------------------------------g

Canning Food preservationthrough canning was inventedin 1809 by Frenchman Nicolas-François Appert (c. 1750–1841).Tin-plated cans were first usedfor canning in 1810 by Englishinventor Peter Durand. Com-mercial canning was brought tothe United States in 1821 whenit was introduced by the WilliamUnderwood Company in Boston.In 1874, the canning process wasgreatly improved when cans werefirst heated by high-pressuresteam. The high pressure in thisprocess kept cans from burstingduring heating.

Using the Figure ----g

Allotropes Many elements haveseveral forms, called allotropes. Forexample, oxygen gas and ozoneare allotropes of oxygen. Allo-tropes are usually stable at differ-ent temperatures and pressures.For example, diamond, graphite,and buckyballs are allotropes ofcarbon. Refer to Figure 5.l Visual


silicon and germanium

CHAPTER RESOURCESWorkbooks

Math Skills for Science• Checking Division with Multiplicationg

Is That a Fact!Less than 50 years ago, most scientistsbelieved that silicon had little commer-cial use. They didn’t foresee the inven-tion of the silicon transistor chip, whichled the way for the development ofcomputer chips. Now, industrial proc-esses using silicon employ millions ofpeople worldwide. The main siliconproduct, integrated circuits for com-puter and game chips, has changedthe world.


Group 15: Nitrogen Group

Nitrogen, which is a gas at room temperature, makesup about 80% of the air you breathe. Nitrogenremoved from air can be reacted with hydrogen tomake ammonia for fertilizers.

Although nitrogen is not very reactive, phosphorusis extremely reactive, as shown in Figure 6. In fact,in nature phosphorus is only found combined withother elements.

Figure 6 Simply striking a match on the side of this box causes chemicals on the match to react with phosphorus on the box and begin to burn.

Figure 7 This diver is breathing a mix-ture that contains oxygen gas.

Group contains: two nonmetals, two metalloids, and two metalsElectrons in the outer level: 5Reactivity: varies among the elementsOther shared properties: solids at room temperature (except for nitrogen)

Group 16: Oxygen Group

Oxygen makes up about 20% of air. Oxygen is neces-sary for substances to burn. Oxygen is also importantto most living things, such as the diver in Figure 7. Sul-fur is another commonly found member of Group 16.Sulfur can be found as a yellow solid in nature. Itis used to make sulfuric acid, the most widely usedcompound in the chemical industry.

✓✓Reading Check Which gases from Groups 15 and 16 make up most of the air you breathe?

Group contains: three nonmetals, one metalloid, and one metalElectrons in the outer level: 6Reactivity: ReactiveOther shared properties: All but oxygen are solid at room temperature.

For another activity related to this chapter, go to go.hrw.com and type in the keyword HP5PRTW.

ArsenicAs33

PhosphorusP15

NitrogenN7

AntimonySb51

BismuthBi83

UnunpentiumUup

115

SeleniumSe34

SulfurS16

OxygenO8

TelluriumTe52

PoloniumPo84

Research -------------------------------------------g

PORTFOLIO

Sulfuric Acid Ask stu-dents to find out more

about sulfur and sulfuric acid.Sulfuric acid is widely used inthe chemical industry. Havestudents find out how and whyit is so widely used. Studentsmay also investigate sulfur, sul-furic acid, smog, and acid rain.l Verbal/Logical

CONNECTIONCONNECTION vvHistory --------------------------------------------------a

Writing Sulfur Sulfur was usedby prehistoric people as apigment for cave draw-

ings. It was also used in Egyptianceremonies 4,000 years ago andin Chinese fireworks in about500 BCE. Sulfur is even men-tioned in Greek mythology. Havestudents write a report, make aposter, or prepare a presentationon the ways that sulfur was usedbefore it was recognized as an element in 1777.l Verbal ee


nitrogen and oxygen


Science Skills• Finding Useful Sourcesg


Group 17: Halogens

Halogens (HAL oh juhnz) are very reactive nonmetals because their atoms need to gain only one electron to have a complete outer level. The atoms of halogens combine readily with other atoms, especially met-als, to gain that missing electron. The reaction of a halogen with a metal makes a salt, such as sodium chloride. Both chlorine and iodine are used as disin-fectants. Chlorine is used to treat water. Iodine mixed with alcohol is used in hospitals.

Although the chemical properties of the halogens are similar, the physical properties are quite different, as shown in Figure 8.

halogen one of the elements of Group 17 of the periodic table (fluorine, chlorine, bromine, iodine, and astatine); halogens combine with most metals to form salts

Group contains: nonmetalsElectrons in the outer level: 7Reactivity: very reactiveOther shared properties: poor conductors of electric current; violent reactions with alkali metals to form salts; never in uncombined form in nature

Physical Properties of Some HalogensFigure 8

Water Treatment Chlorine has been used to treat drinking water since the early 20th century. Chlorinating water helps protect people from many diseases by killing the organisms in water that cause the diseases. But there is much more to water treatment than just adding chlorine. Research how a water treatment plant purifies water for your use. Construct a model of a treatment plant. Use labels to describe the role of each part of the plant in treating the water you use each day.

BromineBr35

ChlorineCl17

FluorineF9

IodineI53

AstatineAt85

Chlorine is a yellowish green gas.

Bromine is a dark red liquid.

Iodine is a dark gray solid.


CulturalAwarenessCulturalAwareness g

The Curies About a century ago, Marie Sklodowska Curie (1867–1934) made many contributions to the study of radioactivity and radio-active elements. In 1903, Marie, her husband, Pierre Curie (1859–1906), and French physicist Henri Becquerel (1852–1908) were awarded the Nobel Prize in physics for their contribu-tions to understanding radioactivity. The Curies dis-covered the radioactive ele-ments polonium and radium and isolated samples of these elements from tons of ore. For her discoveries of polo-nium and radium, Marie Curie was awarded the Nobel Prize in chemistry in 1911.

CONNECTION toCONNECTION toAstronomy -------------------------------------------g

Element Factories Stars seem to be the factories that make the naturally occurring elements throughout the universe. Students can find information about and photographs of areas in the uni-verse where new stars are born and areas where old stars have exploded. Have students research how elements may be generated or changed in these violent reactions. l Logical

h-----------------------------a

Salt Formers The word halogen comes from the Greek words meaning “salt for-mer.” Sodium chloride, or table salt, is composed of the halogen chlorine and the alkali metal sodium. Have students research halogens and their uses and then prepare a chart or a poster that shows what the stu-dents learned. l Visual/Logical

Group 18: Noble Gases

Noble gases are unreactive nonmetals and are in Group 18 of the periodic table. The atoms of these elements have a full set of electrons in their outer level. So, they do not need to lose or gain any electrons. Under normal conditions, they do not react with other elements. Earth’s atmosphere is almost 1% argon. But all the noble gases are found in small amounts.

The unreactivity of the noble gases makes them useful. For example, ordinary light bulbs last longer when they are filled with argon. Because argon is unreactive, it does not react with the metal filament in the light bulb even when the filament gets hot. A more reactive gas might react with the filament, caus-ing the light to burn out. The low density of helium makes blimps and weather balloons float. Another popular use of noble gases is shown in Figure 9.

Why are noble gases unreactive?

Hydrogen

The properties of hydrogen do not match the prop-erties of any single group, so hydrogen is set apart from the other ele ments in the table. Hydrogen is above Group 1 because atoms of the alkali metals also have only one electron in their outer level. Atoms of hydrogen can give away one electron when they join with other atoms. However, the physical properties of hydrogen are more like those of nonmetals than those of metals. So, hydrogen really is in a group of its own. Hydrogen is found in stars. In fact, it is the most abundant element in the universe. Its reactive nature makes it useful as a fuel in rockets, as shown in Figure 10.

noble gas one of the elements of Group 18 of the periodic table (helium, neon, argon, krypton, xenon, and radon); noble gases are unreactive

Figure 10 Hydrogen reacts violently with oxygen. The hot water vapor that forms as a result of this reaction helps guide the space shuttle into orbit.

Figure 9 In addition to neon, other noble gases can be used to make “neon” lights.

Group contains: nonmetalsElectrons in the outer level: 8 (except helium, which has 2)Reactivity: unreactiveOther shared properties: colorless, odorless gases at room temperature

Electrons in the outer level: 1Reactivity: reactiveOther properties: colorless, odorless gas at room tem-perature; low density; explosive reactions with oxygen

✓Reading Check

KryptonKr36

ArgonAr18

NeonNe10

HeliumHe

2

XenonXe54

RadonRn

86

HydrogenH1


Reteaching---------------------------------------b

Mendeleev, May I? To help students remember the proper-ties of the groups, use chalk to draw a giant periodic table on the ground. Divide students into groups and play a game of Mother, may I? Give each group a command such as “Go to the group whose elements are unreactive.” Students must decide where on the periodic table they should go and must ask you “Mendeleev, may we go to Group 18?” If they are correct, they should move to that area of the periodic table. l Kinesthetic/Interpersonal

Quiz ---------------------------------------------------------------------g

1. Using the periodic table, determine which two groups include highly reactive metals. (on the left, Groups 1 and 2)

2. What are the actinides? What is one characteristic of all actinides? (the elements that follow actinium and that have atomic numbers 90–103; All actinides are radioactive.)

3. Of the gases oxygen, argon, chlorine, and neon, which two would be the most chem-ically reactive? (Oxygen and chlorine would be. Argon and neon are in Group 18, which con-sists of the noble gases, which are very unreactive.)


Atoms of noble gases have a full set of electrons in their outer level. MISCONCEPTION

ALERT

Inert Gases Noble gases were originally called inert gases becauseit was thought that they would not react with any elements. However, scientists are able to use high tempera-tures and pressures to cause some of the elements in Group 18 to react. Thus, the term inert is incorrect, and the term noble is preferred.

For a variety of links related to thischapter, go to www.scilinks.org

SummarySummary

Review

• Alkali metals (Group 1) are the mostreactive metals. Atoms of the alkalimetals have one electron in theirouter level.

• Alkaline-earth metals (Group 2) are lessreactive than the alkali metals are. Atomsof the alkaline-earth metals have twoelectrons in their outer level.

• Transition metals (Groups 3–12) includemost of the well-known metals and thelanthanides and actinides.

• Groups 13–16 contain the metalloidsand some metals and nonmetals.

• Halogens (Group 17) are very reactive non-metals. Atoms of the halogens have sevenelectrons in their outer level.

• Noble gases (Group 18) are unreactivenonmetals. Atoms of the noble gases havea full set of electrons in their outer level.

• Hydrogen is set off by itself in the periodictable. Its properties do not match theproperties of any one group.

Using Key Terms

Complete each of the following sentences bychoosing the correct term from the word bank.

noble gas alkaline-earth metalhalogen alkali metal

1. An atom of a(n) has a full set of electrons inits outermost energy level.

2. An atom of a(n) has one electron in itsoutermost energy level.

3. An atom of a(n) tends to gain one electronwhen it combines with another atom.

4. An atom of a(n) tends to lose two electronswhen it combines with another atom.

Understanding Key Ideas

5. Which group contains elements whose atomshave six electrons in their outer level?

a. Group 2 c. Group 16b. Group 6 d. Group 18

6. What are two properties of the alkali metals?

7. What causes the properties of elements in agroup to be similar?

8. What are two properties of the halogens?

9. Why is hydrogen set apart from the otherelements in the periodic table?

10. Which group contains elements whose atomshave three electrons in their outer level?

Interpreting Graphics

11. Look at the model of an atom below. Does themodel represent a metal atom or a nonmetalatom? Explain your answer.

Critical Thinking

12. Making Inferences Why are neither the alkalimetals nor the alkaline-earth metals founduncombined in nature?

13. Making Comparisons Compare the elementhydrogen with the alkali metal sodium.

Topic: Alkali Metals; Halogens andNoble Gases

SciLinks code: HSM0043; HSM0711

AlternativeAssessment ---------------------------g

Concept Mapping Have stu-dents prepare a concept map ofthe Periodic Table of the Elements,showing the groups as discussedin this chapter and the charac-teristics of each group or set ofgroups. Students do not have toshow each individual element oreach separate group. l Visual

Answers to Section Review

1. noble gas2. alkali metal3. halogen4. alkaline-earth metal5. c6. Answers may vary but

could include that alkali metalshave one electron in their outerlevel; are very reactive; aresoft, silver colored, and shiny;and have a low density.

7. having the same number ofelectrons in the outer level oftheir atoms

8. Answers may vary butcould include that halogenshave seven electrons in theirouter level, are very reactive,conduct electric current poorly,react violently with alkali met-als to form salts, and are neverfound uncombined in nature.

9. The properties of hydrogendo not match the propertiesof any single group.

10. boron group (Group 13)11. metal; The model shows two

electrons in the outer level, sothe atom represented is mostlikely a metal.

12. They are so reactive that theyreact with water or oxygen inthe air.

13. Both hydrogen and sodiumhave one electron in their outerlevel. Atoms of both elementsgive away one electron whenjoining with other atoms. Buthydrogen is a nonmetal andis a gas at room temperature,whereas sodium is a metal andis a solid at room temperature.

CHAPTER RESOURCES


• Section Quizg• Section Reviewg• Vocabulary and Section Summaryg• Reinforcement Worksheetb• Critical Thinkinga

Technology

Interactive Explorations CD-ROM• Element of Surpriseg

CRF


Model-Making Lab

Create a Periodic TableYou probably have classification systems for many things inyour life, such as your clothes, your books, and your CDs. Oneof the most important classification systems in science is theperiodic table of the elements. In this lab, you will developyour own classification system for a collection of ordinaryobjects. You will analyze trends in your system and compareyour system with the periodic table of the elements.

Procedure

1 Your teacher will give you a bag of objects. Your bag is missingone item. Examine the items carefully. Describe the missingobject in as many ways as you can. Be sure to include thereasons why you think the missing object has the charac-teristics you describe.

2 Lay the paper squares out on your desk or table so that youhave a grid of five rows of four squares each.

3 Arrange your objects on the grid in a logical order. (You mustdecide what order is logical!) You should end up with oneblank square for the missing object.

4 Record a description of the basis for your arrangement.

Classify objects based ontheir properties.

Identify patterns and trendsin data.

• bag of objects

• balance, metric

• meterstick

• paper, graphing (2 sheets)

• paper, 3 � 3 cm squares (20)

OBJECTIVES

MATERIALS

Model-MakingModel-Making LabLab

Create a Periodic Table

Teacher’s Notes

Time RequiredOne to two 45-minute classperiods

Lab Ratings

rTeacher Prep fff

Student Set-Up f

Concept Level fff

Clean Up f

M A T E R I A L SFor each group of 2–4 students,assemble a collection of 20 objects(5 sets of 4 objects). You should pro-vide a bag containing 19 of theseobjects. A recommended collectionof objects includes sets of coins(pennies, nickels, dimes, and quar-ters), sets of buttons that are similarbut vary in diameter, and washersthat vary in diameter. Other objects,such as nuts, bolts, and paper cir-cles, will work and may be obtainedeasily. The difference in massesshould be large enough for a beambalance to detect. Ideally, each set(one column on the table) should beof the same material and thicknessand vary only in diameter.

Preparation NoteYou may have students preparethe 20 squares of paper, but thelab will go faster if the squaresare prepared ahead of time.

CHAPTER RESOURCES


CRF • Datasheet for Chapter Lab• Lab Notes and Answers

Technology

Classroom Videos• Lab Video

Norman Holcomb

Marion Elementary SchoolMaria Stein, Ohio

Holt Lab Generator CD-ROMSearch for any lab by topic, standard, difficulty level,or time. Edit any lab to fit your needs, or create yourown labs. Use the Lab Materials QuickList softwareto customize your lab materials list.

CLASSROOM

TESTED& APPRO

VED


5 Measure the mass (g) and diameter (mm) of each object, and record your results in the appropriate square. Each square (except the empty one) should have one object and two written measurements on it.

6 Examine your pattern again. Does the order in which your objects are arranged still make sense? Explain.

7 Rearrange the squares and their objects if necessary to improve your arrangement. Record a description of the basis for the new arrangement.

8 Working across the rows, number the squares 1 to 20. When you get to the end of a row, continue numbering in the first square of the next row.

9 Copy your grid. In each square, be sure to list the type of object and label all measurements with appropriate units.

Analyze the Results

1 Constructing Graphs Make a graph of mass (y-axis) versus object number (x-axis). Label each axis, and title the graph.

2 Constructing Graphs Now make a graph of diameter ( y-axis) versus object number (x-axis).

Draw Conclusions

3 Analyzing Graphs Discuss each graph with your classmates. Try to identify any important features of the graph. For example, does the graph form a line or a curve? Is there anything unusual about the graph? What do these features tell you? Record your answers.

4 Evaluating Models How is your arrange-ment of objects similar to the periodic table of the elements found in this textbook? How is your arrangement different from that periodic table?

5 Making Predictions Look again at your pre-diction about the missing object. Do you think your prediction is still accurate? Try to improve your description by estimating the mass and diameter of the missing object. Record your estimates.

6 Evaluating Methods Mendeleev created a periodic table of elements and predicted characteristics of missing elements. How is your experiment similar to Mendeleev’s work?

Chapter 12 • Chapter Lab 353

Analyze the Results

1. Graphs should be similar to sample graph A.

2. Graphs should be similar to sample graph B.

Draw Conclusions

3. Answers may vary. The primary feature is the repeating pattern of increases. This pattern in the first graph indicates the peri-odic nature of the mass of the items. This pattern in the sec-ond graph indicates the peri-odic nature of the diameter of the items.

4. Answers may vary. Similarities include repeating patterns (such as patterns of increasing mass) across the table. Differences may include no consistent family traits and no chemical properties associated with position in the table.

5. Answers may vary depending on the student’s original predic-tion. Accept all reasonable answers. (You may wish to provide the students with the missing object so that they can further evaluate their prediction.)

6. This experiment is similar in that a pattern that helped identify characteristics of a missing object was identified.


Whiz-Bang Demonstrations • Waiter, There’s Carbon in My

Sugar Bowl! b

Inquiry Labs • The Chemical Side of Light g

Long-Term Projects & Research Ideas • It’s Element-ary a

Mas

s

Object number

A

Dia

met

er

Object number

B

7 Which of the following items is NOT found on the periodic table?

a. the atomic number of each elementb. the name of each elementc. the date that each element was

discoveredd. the atomic mass of each element

8 Which of the following statements about the periodic table is false?

a. There are more metals than non-metals on the periodic table.

b. Atoms of elements in the same group have the same number of electrons in their outer level.

c. The elements at the far left of the periodic table are nonmetals.

d. Elements are arranged by increasing atomic number.

9 Which of the following statements about alkali metals is true?

a. Alkali metals are generally found in their uncombined form.

b. Alkali metals are Group 1 elements.c. Alkali metals should be stored

underwater.d. Alkali metals are unreactive.

0 Which of the following statements about elements is true?

a. Every element occurs naturally.b. All elements are found in their

uncombined form in nature.c. Each element has a unique atomic

number.d. All of the elements exist in approxi-

mately equal quantities.

Complete each of the following sen-tences by choosing the correct term from the word bank.

group periodalkali metals halogensalkaline-earth metals noble gases

1 Elements in the same vertical column on the periodic table belong to the same .

2 Elements in the same horizontal row on the periodic table belong to the same .

3 The most reactive metals are .

4 Elements that are unreactive are called .

Multiple Choice

5 Mendeleev’s periodic table was useful because it

a. showed the elements arranged by atomic number.

b. had no empty spaces.c. showed the atomic number of the

elements.d. allowed for the prediction of the

properties of missing elements.

6 Most nonmetals are

a. shiny.b. poor conductors of electric current.c. fl attened when hit with a hammer.d. solids at room temperature.

USING KEY TERMS

UNDERSTANDING KEY IDEAS


ANSWERS

Using Key Terms1. group2. period3. alkali metals4. noble gases

Understanding Key Ideas5. d6. b7. c8. c9. b

10. c

Assignment GuideSECTION QUESTIONS

1 1–2, 5–8, 10–12, 15–16, 19–20

2 3–4, 9, 13–14, 18

1 and 2 17

?

Short Answer

q How is Moseley’s basis for arrang-ing the elements different fromMendeleev’s?

w How is the periodic table like acalendar?

Math Skills

Examine the chart of the percentagesof elements in the Earth’s crust below.Then, answer the questions that follow.

e Excluding the “Other” category, whatpercentage of the Earth’s crust arealkali metals?

r Excluding the “Other” category, whatpercentage of the Earth’s crust arealkaline-earth metals?

tConcept Mapping Use the followingterms to create a concept map: periodictable, elements, groups, periods, metals,nonmetals, and metalloids.

yForming Hypotheses Why was Men-deleev unable to make any predictionsabout the noble gas elements?

u Identifying Relationships When anelement that has 115 protons in itsnucleus is synthesized, will it be ametal, a nonmetal, or a metalloid?Explain your answer.

iApplying Concepts Your classmateoffers to give you a piece of sodiumthat he found on a hiking trip. What isyour response? Explain.

oApplying Concepts Identify eachelement described below.

a. This metal is very reactive, hasproperties similar to those of mag-nesium, and is in the same period asbromine.

b. This nonmetal is in the same groupas lead.

p Study the diagram below to determinethe pattern of the images. Predict themissing image, and draw it. Identifywhich properties are periodic andwhich properties are shared within agroup.

46.6% O

27.7% Si

2.0% Mg

2.8% Na

3.6% Ca

5.0% Fe

8.1% Al

2.6% K

1.6% Other

CRITICAL THINKING

INTERPRETING GRAPHICS

11. Moseley arranged elements byincreasing atomic number.Mendeleev arranged elementsby increasing atomic mass.

12. Both are periodic. The periodictable has repeating propertiesof elements. The calendar hasrepeating days and months.

13. 5.4% (sodium and potassium)14. 5.6% (magnesium and calcium)

Critical Thinking15. An answer to this

exercise can befound at the endof this book.

16. Mendeleev could make predic-tions only about elementswhere there were clear gaps inhis table. Because no noblegases were known at the time,there were no obvious gaps inthe table and no way that hecould have known that a wholecolumn was missing.

17. metal; it will be located belowthe metal bismuth to the left ofthe zigzag

18. I would tell my classmate thathe didn’t find sodium. Sodium isvery reactive and cannot befound uncombined in nature.Sodium would react with oxy-gen and water in the air to formcompounds.

19. a. calciumb. carbon

Interpreting Graphics20.

Periodic properties are theorder of the shapes and thenumber of lines inside theshape. The properties sharedin a group are the shape andthe color of the lines insidethe shape.

CHAPTER RESOURCES


• Chapter Reviewg• Chapter Test Ag• Chapter Test Ba• Chapter Test Cs• Vocabulary Activityg

Workbooks

Study Guide• Study Guide is also available in Spanish.

CRF

Chapter 12 • Chapter Review 355

MISCONCEPTIONALERT

READING

READINGRead each of the passages below. Then, answer the questions that follow each passage.

Passage 1 Napoleon III (1808–1873) ruled as emperor of France from 1852 to 1870. Napoleon III was the nephew of the famous French military leader and emperor Napoleon I. Early in his reign, Napoleon III was an authoritarian ruler. France’s economy did well under his dictatorial rule, so the French rebuilt cities and built railways. During the 1850s and 1860s, Napoleon III used aluminum dinnerware because aluminum was more valuable than gold. Despite his wealth and French eco-nomic prosperity, Napoleon III lost public support and popularity. So, in 1860, he began a series of reforms that allowed more individual freedoms in France.

1. What is the meaning of the word authoritarianin the passage?

A controlling people’s thoughts and actionsB writing books and storiesC being an expert on a subjectD being very wealthy

2. Which of the following statements best describes why Napoleon III probably changed the way he ruled France?

F He was getting old.G He was unpopular and had lost public

support.H He had built as many railroads as he could.I He used aluminum dinnerware.

3. According to the passage, in what year did Napoleon III die?

A 1808B 1873C 1860D 1852

Passage 2 Named after architect Buckminster Fuller, buckyballs resemble the geodesic domes that are characteristic of the architect’s work. Excitement over buckyballs began in 1985, when scientists projected light from a laser onto a piece of graphite. In the soot that remained, researchers found a completely new kind of molecule! Buckyballs are also found in the soot from a candle flame. Some scientists claim to have detected buckyballs in space. In fact, one suggestion is that buckyballs are at the center of the condensing clouds of gas, dust, and debris that form galaxies.

1. Which of the following statements correctly describes buckyballs?

A They are a kind of dome-shaped building.B They are shot from lasers.C They were unknown before 1985.D They are named for the scientist who

discovered them.

2. Based on the passage, which of the following statements is an opinion?

F Buckyballs might be in the clouds that form galaxies.

G Buckyballs are named after an architect.H Scientists found buckyballs in soot.I Buckyballs are a kind of molecule.

3. According to the passage, why were scientists excited?

A Buckyballs were found in space.B An architect created a building that

resembled a molecule.C Buckyballs were found to be in condensing

clouds of gas that form galaxies.D A new kind of molecule was found.

Passage 11. A2. G3. B

Question 1: Some students may think that the word authoritarianderives from either the word author(a writer of books and stories) or the word authority (an expert on a sub-ject) because these words appear closely related. However, the correct meaning can be determined by notic-ing that the passage contrasts the early rule of Napoleon III with his later rule, in which he granted more individ-ual freedoms.

Passage 21. C2. F3. D

Question 1: The passage states that the excite-ment over buckyballs began when they were dis-covered in 1985. Buckyballs are not dome-shaped buildings; they only resemble the buildings. Shooting lasers at graphite can make buckyballs, but the buckyballs themselves are not shot from the laser. The person for whom the buckyballs are named, Buckminster Fuller, did not discover them. Fuller was an architect who was known for design-ing buildings that used geodesic domes, which happen to resemble buckyballs.


Teacher’s NoteTeacher’s NoteTo provide practice under more realistic testing conditions, give students 20 minutes to answer all of the questions in this Standardized Test Preparation.

Answers to the standardized test preparation can help you identify student misconcep-tions and misunderstandings.

Stand

ardized

Test Prep

aration

1. Which of the following statements is correct for the elements shown?

A Lithium has the greatest atomic number.B Sodium has the least atomic mass.C Atomic number decreases as you move

down the column.D Atomic mass increases as you move down

the column.

2. Which of the following statements best describes the outer electrons in atoms of the elements shown?

F The atoms of each element have 1 outer-level electron.

G Lithium atoms have 3 outer-level electrons, sodium atoms have 11, and potassium atoms have 19.

H Lithium atoms have 7 outer-level electrons, sodium atoms have 23, and potassium atoms have 39.

I The atoms of each element have 11 outer-level electrons.

3. The elements featured in the image belong to which of the following groups?

A noble gasesB alkaline-earth metalsC halogensD alkali metals

1. Elvira’s house is 7.3 km from her school. What is this distance expressed in meters?

A 0.73 mB 73 mC 730 mD 7,300 m

2. A chemical company is preparing a shipment of 10 g each of four elements. Each element must be shipped in its own container that is completely fi lled with the element. Which container will be the largest?

F the container of aluminumG the container of arsenicH the container of germaniumI the container of silicon

3. Arjay has samples of several common elements. Each element has a unique atomic mass (expressed in amu). Which of the following lists shows the atomic masses in order from least to greatest?

A 63.55, 58.69, 55.85, 58.93B 63.55, 58.93, 58.69, 55.85C 55.85, 58.69, 58.93, 63.55D 55.85, 63.55, 58.69, 58.93

6.9Lithium

3

23.0Sodium

11

39.1Potassium

19

Read each question below, and choose the best answer.

Use the image of the periodic table below to answer the questions that follow.

ElementDensity(g/cm3)

Mass(g)

Aluminum 2.702 10

Arsenic 5.727 10

Germanium 5.350 10

Silicon 2.420 10

INTERPRETING GRAPHICS MATH INTERPRETING GRAPHICS1. D2. F3. D

Question 1: The atomic mass and the atomic number of elements in a group increase as you move from top to bottom in the group. Students often have trouble decoding questions that ask for a ranking of quantity or size in a given direction. In this question, students must analyze the value of the atomic mass or the atomic number while moving in a stated direction along the group. An error in either thought process can result in choosing an incorrect answer.

MATH1. D2. I3. C

Question 2: Each container con-tains 10 g of an element. Therefore, the size of each container will be determined by the density of the el ement in the container. The element that has the highest density, arsenic, will require the smallest container. The element that has the lowest density, silicon, will require the largest container. Students who have difficulty with this item might benefit by comparing the volumes of equal masses of cotton and lead.

Chapter 12 • Standardized Test Preparation 357

CHAPTER RESOURCES


CRF • Standardized Test Preparation g

State Resources

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in Action

Sciencein Action

Language ArtsImagine that you are trapped within a buckyball. Write a one-

page short story describing your experience. Describe the windows in your molecular prison.

WRITINGSKILL

MathFireworks can cost between $200 and $2,000 each. If a show uses 20 fireworks that cost $200 each, 12 fireworks that cost $500 each, and 10 fireworks that cost $1,200 each, what is the total cost for the fireworks?

Weird ScienceBuckyballsIn 1985, scientists found a completely new kind of molecule! This carbon molecule has 60 carbon atoms linked together in a shape similar to that of a soccer ball. This molecule is called a buckyball. Buckyballs have also been found in the soot from candle flames. And some scientists claim to have detected buckyballs in space. Chemists have been trying to identify the molecules’ properties. One property is that a buckyball can act like a cage and hold smaller substances, such as individual atoms. Buckyballs are both slip-pery and strong. Scientists are exploring their use in tough plastics and cutting tools.

Science, Technology,

and SocietyThe Science of FireworksExplosive and dazzling, a fireworks display is both a science and an art. More than 1,000 years ago, the Chinese made black powder, or gunpowder. The powder was used to set off firecrackers and primitive missiles. The shells of fireworks contain several different chemicals. Black powder at the bottom of the shell launches the shell into the sky. A second layer of black powder ignites the rest of the chemicals and causes an explosion that lights up the sky! Colors can be created by mixing chemicals such as strontium (for red), magnesium (for white), or copper (for blue) with the gunpowder.

Weird Science

BackgroundThe hexagons and pentagons of Buckminster Fuller’s geodesic domes provide great stability because they distribute stress evenly. The buckyball, C60, is one member of a large family of carbon “cages” called fullerenes.Fullerenes that have fewer than 60 carbon atoms are called buckybabies. Buckytubes have more than 60 carbon atoms and are shaped like cylinders of spiraling honeycombs.

Scientists know that high tem-peratures are needed to form buckyballs, so they look for buckyballs in intensely heated sites, such as asteroid craters and lightning strikes. Buckyball mol-ecules are found in greatest abundance in soot.

Science, Technology,

and Society

BackgroundThe colors in a fireworks display depend on the wavelengths of the light emitted by different chemicals. Light that has the shortest wavelength appears vio-let in color. Light that has the longest wavelength appears red. Refer to the chart at the bottom of the page for the colors pro-duced by various elements. Charcoal gives the fireworks a sparkling, flaming tail. Element Color

Sodium yellow

Barium green

Copper blue

Strontium red

Lithium bright red

Calcium dark red

Magnesium white

Answer to Language Arts Activity

The shapes of the windows are pentagons and hexagons. Each pentagon is surrounded by five hexagons.

Answer to Math Activity

Students should be aware that a fireworks display is costly. The cost of the display is (20 � $200) � (12 � $500) � (10 � $1200) �$22,000.


Write a newspaper editorial to express

an opinion for or against the Manhattan Project. Be sure to include information to support your view.

WRITINGSKILL

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articles related to this chapter by visiting go.hrw.com. Just type in the keyword HP5CS12.

Glenn T. SeaborgMaking Elements When you look at the periodic table, you can thank Dr. Glenn Theodore Seaborg and his colleagues for many of the actinide elements. While work-ing at the University of California at Berkeley, Seaborg and his team added a number of elements to the periodic table. His work in identifying properties of plutonium led to his working on the top-secret Manhattan Project at the University of Chicago. He was outspoken about the beneficial uses of atomic energy and, at the same time, opposed the production and use of nuclear weapons.

Seaborg’s revision of the layout of the periodic table—the actinide concept—is the most significant since Mendeleev’s original design. For his scientific achievements, Dr. Seaborg was awarded the 1951 Nobel Prize in Chemistry jointly with his col-league, Dr. Edwin M. McMillan. Element 106, which Seaborg neither discovered nor created, was named seaborgium in his honor. This was the first time an element had been named after a living person.

Teaching Strategy-- GENERAL

Show students that each element produces a certain color. Obtain samples of calcium chloride, strontium chloride, and sodium chloride. To prepare 0.5 M solutions, dissolve the fol-lowing quantities in separate containers with enough water to make 100 mL of each solution: 5.5 g CaCl2, 8.83 g SrCl2•H2O,and 2.9 g NaCl. Dip a different wooden splint in each solution, and use tongs to insert each splint into the flame of a porta-ble burner to burn the chemical from the splint. Try not to ignite the splints. The splints can be dipped into the solutions again if necessary.

People in Science

BackgroundSeaborg was greatly influenced by his teachers, beginning with his high school science instructor, Dwight L. Reid. When Seaborg was a graduate student at the University of California, Berkeley, his instructors included several eminent scientists, such as Gilbert N. Lewis, Axel R. Olson, William F. Giauque, and J. Robert Oppenheimer. Dr. Seaborg was a strong pro ponent of education. He was committed to science education and to the creation of a scientifically literate society.

Answer to Social Studies Activity

The editorials written by students should convey a strong opinion either for or against the Manhattan Project and should incorporate infor-mation found through research to support that opinion. Students should not simply report the information that they find.

Chapter 12 • Science in Action 359

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