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The Elements

Chapter 7

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Section 7.1 Prop of s-block

Objectives: Explain how elements in a given group are both

similar and different

Discuss the properties of H

Describe and compare the properties of alkali and alkaline earth metals

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General Info

92 naturally occurring elements He is the 2nd most common element in

universe, and is much less on Earth O most abundant on Earth Atomic # > 92 do not exist in nature

They’re synthetic Created in labs or nuclear reactors

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Representative elements

1A 8A s and p orbital Diagonal relationships

Have common characteristics with elements diagonal to them

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Hydrogen

1A because 1 valence e- 7A characteristics Contains metallic and nonmetallic properties Not considered part of any group

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Hydrogen history

1766 Henry Cavendish discovered H “Flammable air” b/c burned when ignited in air

1783 Lavoisier named H Greek “hydro”-water, “genes” - to form

Picture source Wikipedia.com

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Hydrogen Isotopes

Protium 99.985% No neutrons

Deuterium 0.015% 1 neutron

Tritium 2 neutrons Radioactive Produced when cosmic rays bombard water in atmosphere “heavy water”

Picture source Wikipedia.com

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Hydrogen bonding

Gain e- H + H stable configuration of He

Lose e- H+ ion with no e-

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Group 1A: Alkali metals

Li Na K Rb Cs Fr

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Alkali Metals

Arabic “al-qili” “Ashes of saltwort plant”

Easily lose valence e- 1+ charge ion Soft like cold butter Highly reactive Lab samples stored in oil to prevent O

reaction Good conductor of heat/electricity

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Lithium (Li) Lightest alkali metal Found in water, soil and rocks Least reactive of alkali metals Li & Mg diagonal relationship Used in

batteries – extend life electric cars Dehumidifiers – absorbs water Li carbonate – strengthens glass, drug bipolar

disorder Alloys – plane parts b/c strong & lightweight

Picture source http://www.webelements.com/webelements/elements/text/Li/key.html

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Na & K Most abundant Na vapor lamps Heat exchanger in nuclear reactors Humans and vertebrates need in diets

K+ most common in cells Na+ most common in fluid outside cells When nerve cell stimulated

K+ moves outside the cell when Na+ moves into the cell

Picture source Wikipedia.com

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More Na and K info

NaCl most common Na compound Prevent spoiling Preserve food KCl – salt substitute K compound found in fertilizers for plant

growth and development KNO3 – explosives for fireworks

Picture source http://www.webelements.com/webelements/elements/text/Na/key.html

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Other Alkali metals

Rb extremely reactive 40°C mp Burst into flames when exposed to air

Fr Most reactive Rare radioactive element

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Group 2A: Alkaline Earth metals

Be Mg Ca Sr Ba Ra

All Picture sources from http://www.webelements.com/webelements/elements/text/Ra/key.html

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Alkaline Earth Metals

Medieval alchemist classified solids that did not melt in their fires as “earths”

AEM + O2 oxides form thin oxide coating Shiny solids Harder than AM Less reactive than AM Found combined w/ O and other nonmetals Lose 2 valence e- 2+ charge

Ca, Sr, Ba react with water Be no react with water

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Beryllium (Be)

Lightest in Group 2A Beryl is Be + Al + Si + O Al & Be have diagonal relationship Used to moderate n0 in nuclear reactors Be-Cu tools used in petroleum refineries

Picture source from http://www.webelements.com/webelements/elements/text/Be/key.html

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Calcium (Ca) Essential for humans

Maintain teeth and bones Calcium carbonate

Limestone, chalk, marble Coral reefs Antacid tablets Toothpaste abrasives Emery boards and sand paper Limestone used to build Roman aqueduct

Calcium carbonate decomposes into lime

Picture source from http://www.webelements.com/webelements/elements/text/Ca/key.html

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Lime

One of the most important industrial compounds

Manufacturing steel, paper and glass Make soil more acidic Wastewater treatment plants Remove pollutants from smokestacks Lime + water + sand = mortar (paste)

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Magnesium (Mg)

Alloys (Mg + Al + Zn) as strong as steel but lighter

Plants chlorophyll molecules contain Mg 2+

Humans muscle function and metabolism Hard water is increase in Ca 2+ and Mg 2+

Interfere with detergent/ soap action Clog pipes, water heaters, and steam irons

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Other AEM Sr

fireworks red color Ba

used in paints and glass diagnostic tool for internal medicine

Ra highly radioactive emit α, β, and γ Painted hands on watches b/c glows at night

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Section 7.2 Prop of p-block

Objectives: Describe and compare properties of p-block

elements

Define allotropes and provide examples

Explain the importance to organisms of selected p-block elements

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Group 3A: Boron Group

B – metalloid Al – abundant metal Ga – rare metal In – rare metal Tl – rare metal

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More Boron Info

Lose 3 e- 3+ charge

Tl 1+ charge Lose p e- only

Very metallic like AM

Ga and In can form 1+ also

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Boron (B)

Chemical properties like Si Borosilicate glass

Withstand extreme temp changes w/o shattering Borax

Large amount comes from CA Mojave Desert Cleaning agent Fireproof insulation

Boric Acid Disinfectant in eye wash

Boron Nitride Second hardest material Super abrasive Used in grinding wheels

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Aluminum (Al)

Most abundant metal 3rd most abundant element of Earth’s crust Combined w/ O or Si Bauxite requires LOTS of energy

Al2O3 major compound in bauxite Abrasive Strengthens ceramics Heat-resistant fabrics

Ruby and sapphires are crystals of Al2O3 Cr red Fe + Ti blue

Alum (Al sulfate) Antiperspirants Remove suspended particles during water purification

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Gallium (Ga) Melts in your hand Used in some thermometers b/c liquid state in large

range (30 – 2403 °C) Gallium arsenide (Ga + As) produce electric

current when absorbs light Used in semiconductor chips Light-powered calculators Solar panels 10x more efficient than Si based

Gallium nitride (Ga + N) Blue lasers Triple DVD storage capacity (3-2 hr movies per DVD) Increase speed and resolution of laser printers Lower cancer cell detection device cost

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Group 4A: Carbon Group

C – nonmetal Si – metalloid Ge – metalloid Sn – metal Pb – metal

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Carbon (C)

Organic chemistry – study of C-based compounds

1828 – 1st C compound synthesized Prior believed only living organisms made C

based compounds Minerals- element or inorganic compound

found in natural as solid crystal Ore- material form which a mineral can be

removed at a reasonable cost Cost to extract not > economic value

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C Allotropes Allotropes – forms of element in same physical state

(SLG) that have different structure and properties Graphite

Softest known material Good lubricant b/c molecules slide 3 C attached

Diamond Hardest known material 4 C attached 3D solid Can cut granite and concrete

Coal Shapeless solid

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Silicon (Si) Second most abundant element on Earth’s crust

after O Used in

Computer chips Solar cells

Silicon dioxide (SiO2) AKA: silica

Quartz + weathering white sand + heat and rapid cooling glass

Si + C silicon carbide Major industrial abrasive

Carborundum – common name Used sticks to sharpen tools

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Pb & Sn Sn Coat steel cans; now use Al cans Bronze alloy Sn + Cu, Zn (little for hardness) Pewter 40% Pb & 60% Sn Softer metal

Pb ancient skeletal analysis dangerously high levels Toxic Used in eating utensils Pipes for plumbing Gasoline additives Paint Car storage batteries (Pb-acid) p. 675-676

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Group 5A: Nitrogen Group

N – nonmetal P – nonmetal As – metalloid Sb – metalloid Bi – metal

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Nitrogen group info

5 valence e-

Forms 3+/- charge ions

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Nitrogen Colorless, odorless, relatively unreactive 78% Earth’s atmosphere Proteins and essential organic compounds Bacteria and clover roots “fix” N Major industrial use

Ammonia Colorless gas with irritating odor Cleaning products N source for plants

25% ammonia nitric acid Produced for explosives Dyes Fertilizers Etching design on metal plates TNT (trinitrotoluene) nitroglycerine

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Phosphorus (P) Allotropes

White P – bursts into flames in air Must be stored in water

Red P – less reactive Formed from white P heated in absence of air Used on matchboxes for striking surface

Black P – white or red heated under high pressure Phosphoric acid phosphate compound

Used in processed cheese, laxatives, baking powder Flame retardant coating on fabrics Grease remover in cleaning products Fertilizers have phosphates

Harmful to environment Normal: phosphates broken down by bacteria nutrients eaten by algae

zooplankton eat algae fish eat zooplankton Increase P ions: increase algae pop keep light from algae below (die)

bacteria decay algae use lots of O other things die no decay and build up of waste occurs lake changes to pond or marsh

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As, Sb, Bi

Oldest known elements As + S arsenic sulfide treat illnesses; As toxic Sb + S antimony sulfide cosmetics to darken

eyebrows and make eyes appear larger Britannia metal – alloy of Sn + Sb; easily shaped Pb storage batteries – contain 7% Sb Bi active ingredient in Pepto – diarrhea and nausea

med Wood’s metal – alloy of Bi, Pb, Sn, Cd

Plug automatic sprinkler; melts when heated and activates sprinkler (water)

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Group 6A: Oxygen Group

O – nonmetal S – nonmetal Se – metalloid Te – metalloid Po – rare metal

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Oxygen Group Info

6 valence e- Nonmetals mainly Gain 2 e- Forms 2 – charge Shares 2 e- for stability when bonded

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Oxygen (O)Allotropes Ozone (O3)

Unstable gas with pungent odor Decomposes when exposed to UV light or heat Produced in auto emissions

Irritates eyes, harmful to lung cells, and affects plant growth negatively O2

21% Earth’s atmosphere Colorless, odorless gas Joseph Priestley (1733-1804) discovered O2

Heated Hg oxide and candle burned more brightly than in air Cellular respiration uses O2 to release energy from carbs Separate from other gases by distillation Canisters store liquid O2

Airplanes have small, individual O2 for emergencies Most abundant element in Earth’s crust Combines with every element except He, Ne, Ar

H2O H2O2 CO CO2

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Sulfur (S) Combined w/ Hg (cinnabar) Combined w/ Pb (galena) Uncombined underground 10 allotropes SO2

Preserve fruit Antibacterial agent Acid rain

90% make sulfuric acid Fertilizers (50%) Steel, paper and paint

H sulfide Rotten egg smell Ocean vents energy source for bacteria Volcanoes

Silver sulfide tarnish

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Selenium (Se)

Na selenate – vitamin supplement contain this Vitamin E prevent cell damage Inhibit cancer cell growth

Locoweed plant – absorbs too much toxic Animals become ill

Light electricity (solar panels) Meters to measure light availability (photography) Charge Se particles create image (photocopiers) Semiconductors (& Te)

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Polonium (Po)

1898 founded by Marie Curie Named after Marie’s home country – Poland Extremely toxic Radioactive Rare metal

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Group 7A: Halogens

F – gas Cl – gas Br – liquid I – solid gas At – radioactive with no known uses

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Halogen Info

“salt formers” Reactive nonmetal Always found combined with other elements

in nature 7 valence e- Share 1 e- or gain 1 e- Forms 1- charge ion

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Fluorine (F) Most electronegative element on PT

Greatest ability to attract e- Most active of all elements

Reacts w/ every element except He, Ne, Ar Latin “fluere” – to flow Fluorite – F + Ca

Lower mp of other minerals, easier to separate from ore F added to toothpaste and water to prevent tooth

decay F + C – non-stick cooking surfaces F + U isotopes gases separate by differences in

mass (U enrichment) provides U-235 fuel for nuclear reactors

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Chlorine (Cl) Deadly gas Reacts w/ nearly all elements 1848 cholera epidemic began in London

25,000 died Culprit: raw sewage flowing into Thames R. 1855 London 1st city to use Cl to disinfect sewage

Bleaching agents by textile and paper industry Remove stains from clothes

Cl compound blocks pain signals during dental work HCl in stomach digests food

Remove rust from steel (pickling) Cl gas

Produced from oil refineries Plastics PVC (polyvinyl chloride)

Floor tiles Pipes for indoor plumbing Garden hoses

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Bromine & Iodine

Ag + Br and Ag + I Coat photographic film

I body maintain thyroid gland Control growth and metabolic rate

Goiter enlarged thyroid gland Lack of I

Seafood excellent source of I Iodized salt (KI, NaI, and NaCl)

Kills bacteria Campers tablets/crystals to disinfect water

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Group 8A: Noble Gases

He Ne Ar Kr Xe Rn

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Noble Gas Info Colorless & unreactive Last natural elements to be discovered Stable 8 valence e- (except He has 2 e-) 1962 – Neil Bartlett, inorganic chemist

created Xe & F compound No known compounds for He, Ne, Ar

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Helium (He)

Lightest Noble Gas First discovered emission spectrum of sun Found in natural gas wells He + O deep sea divers to prevent “bends”

b/c replace N w/ He Lighter than air – blimps, balloons, airships He (l) – coolant for superconducting magnets

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Neon (Ne)

Light display High voltage electricity passes through Ne in gas

discharge tube e- excited e- return to lower state bright orange light released

Ar – blue

He – pale yellow

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Argon & Krypton

Ar most abundant NG on Earth

1% Earth's atmosphere

High temp welding

Both prolong life of filaments in incandescent light bulbs

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Radon (Rn)

Dangerous when inhaled

radioactive

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7.3 d- and f-block

Objectives Compare the e- configuration of transition and

inner transition metals

Describe the properties of transition elements

Explain why some transition metals from compounds with color and some have magnetic properties

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General Info d- block

transitional metals period 4

f- block Inner transition metals

Period 6 Lanthanide series

Lanthanum Period 7

Actinide series Actinium

“B” section

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Transition Metals Electrical conductivity Luster Malleable w/ other metals Little variation in atomic size, electronegativity,

ionization energy across a period Ag best electrical conductor Fe & Ti strength used in structural materials Physical properties determined by e- configuration

Hard solids w/ high bp & mp More unpaired e- in d levels , the increase in hardness and

increase in mp and bp

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Ion formation 2+ charge

Loses 2 s e- Unpaired d 3+ charge or higher 6+ if w/ F or O Most have color (p. 198 Fig. 7-22) UV light “color” for Ti, Sc, Zn Color change indicates ion change (p. 198

Fig. 7-23)

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Magnetism and metals Affected by magnetic field

Moving e- creates magnetic field

Diamagnetism Unaffected by opposite spinning e- or slightly repelled by

magnetic field

Paramagnetism Unpaired e- in valence orbital attracted to magnetic field

Ferromagnetism Strong attraction of substance to magnetic field Ex: Fe, Co, Ni Can form permanent magnets b/c all ions are aligned

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Sources of TM Cu, Ag, Au, Pt, Pd only TM found uncombined

naturally b/c unreactive Metallurgy – applied science studies and designs

methods of extracting metals and their compounds from ores High temp Solutions Electricity

Purify metal extracted by other 2 means Pig iron purified and mixed w/other elements steel w/

3-4% C US imports 60 materials “strategic and critical” b/c

economic and military dependence on these materials Pt, Cr, Co, Mn, W

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Uses of TM

Cu electrical wiring Zn protective coating for other metals Fe steel Alloys jet engines, drill bits, surgical

instruments, armor Pt, Pd, Ni control conditions at which a

reaction will occur when making plastics, petroleum and foods

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What our body NEEDS!!! C, O, H, N, S, P, Na, K, Ca, Mg, Cl –

essential body needs All period 4 TM except Sc and Ti are needed

in the body Fe hemoglobin O grabber cells Zn aid protein digestion, eliminates CO2 Mn & Cu cell respiration Co develop red blood cells Vitamin and mineral supplements

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Inner Transition Metals

Lanthanide Series

Actinide Series

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Lanthanide Series Silvery metals High mp Found mixed together Extremely difficult to separate

“hard to get at” (Greek) Dysprosium Ytterby, Sweden 1st mined Lanth. ores Nd & Pr welder’s goggles absorb high energy

radiation Oxides Y & Eu tv screens & color computer

monitors emit bright red light when excited Misch metal – 50% Ce steel industry remove

C from Fe & steel Movie projectors, high-intensity searchlights, lasers,

tinted sunglasses

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Actinide Series Radioactive 3 exist in nature (Th, Pa, U) Rest are synthetic

Transuranium elements 92 + Created in particle accelerator or nuclear reactor Quickly decay Pu-239 exception (thousands of yrs)

Fuel nuclear power plants

Am smoke detectors

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Credits

Non-cited pictures are from Microsoft Clip Art Information from Glencoe Chemistry Matters,

TX edition Arranged and organized by Michelle Estrada