Gathering Information from the Periodic Table

When one looks at a periodic table, there are many letters and numbers that help identify

the elements and give way to their characteristics. Understanding these letters

and numbers will allow for a better understand of each element.

The Periodic Table

The periodic table was organized over the years to provide scientists information

about the different elements. Both man-made and natural, the elements are placed

in order of things such as atomic mass, atomic number, size and other things.

Dmitrii Mendeleev

The first periodic table was put together by Mendeleev over 130 years ago. He put the

elements in order of relationships of reactivity (how elements react). His table

had holes in it that allowed for other elements to be discovered at a later time.

Today’s Periodic Table

Mendeleev was correct in his holes on his table. Today’s table looks very similar to his table. It lists the elements in order of

their atomic number.

The first 92 elements have been found in nature. All other elements have been man-

made.

Parts of the Periodic Table

Metals- elements possessing similar properties such as metallic luster, reacting well with elements other than metals, and easily conducts electricity. Examples: Copper, Potassium, Sodium

Nonmetals – elements possessing the opposite characteristics of metals. They are often found in the gaseous state. Examples: Hydrogen, Oxygen, Nitrogen

Metalloids found between metals and nonmetals; often have properties of both. Ex: Silicon, Boron

Breaking apart even further

Groups of elements – vertical columnsof elements on the periodic table

Chemical Family – a group of elementsthat includes the number of the column

Period of elements – horizontal row ofelements

1

H1.008

3

Li6.941

11

Na22.99

19

K39.10

37

Rb85.47

55

Cs132.9

87

Fr(223)

ALKALIMETALS

Group IA Characteristics:• The most chemically reactive metals, with the exception of Hydrogen, losing their one valence electron to non-metals• Going down the group, the atomic radius and density of the elements increase

4

Be9.012

12

Mg24.31

20

Ca40.08

38

Sr87.62

56

Ba137.3

88

Ra226

AlkalineEarth Metals

Group IIA Characteristics:

• These elements are also very reactive, losing their two valence electrons to non-metals

9

F

18.9984

17

Cl

35.453

35

Br

79.909

53

I

126.904

85

At

(210)

Group 7A Characteristics:

• These elements all form diatomic molecules.

• With the exception of At, they all react with metals to form salts containing ions with a 1- charge.

2

He

4.0026

10

Ne

20.179

18

Ar

39.498

36

Kr

83.80

54

Xe

131.30

86

Rn

(222)

Group 8A Characteristics:

•These elements exist under normal conditions as

single-atom gases

•Have little chemical reactivity

32

Ge

72.59

50

Sn

118.69

82

Pb

207.19

83

Bi

208.98

13

Al

26.9815

31

Ga

69.72

49

In

114.82

81

Tl

204.37

84

Po

(210)

51

Sb

121.75

MetalsMetals

Characteristics:• These have physical properties such as conduction of heat & electricity, malleability, ductility, and a lustrous appearance•They tend to lose electrons to form positive ions.

7

N

14.0067

15

P

30.9738

33

As

74.9216

6

C

12.011

14

Si

28.086

5

B

10.811

Nonmetals8

O

15.999

16

S

32.064

34

Se

78.96

52

Te

127.6

Characteristics:• These are found in the upper right-hand corner of the table.• Lack the physical properties to deem them metals.•They tend to gain electrons in reactions with metals.

39

Y88.91

57

La138.9

89

Ac(227)

21

Sc44.96

73

Ta180.9105

Db(262)

41

Nb92.91

23

V50.94

72

Hf178.9104

Rf(261)

40

Zr91.22

22

Ti47.88

42

Mo95.94

74

W183.9

24

Cr52.00

106

Sg(263)

48

Cd112.4

30

Zn65.38

80

Hg200.6

47

Ag107.9

29

Cu63.55

79

Au197.0111

Uuu(272)

46

Pd106.4

28

Ni58.69

78

Pt195.1110

Uun(269)

45

Rh102.9

27

Co58.93

77

Ir192.2109

Mt(266)

44

Ru101.1

26

Fe55.85

76

Os190.2108

Hs(265)

43

Tc(98)

25

Mn54.94

75

Re186.2107

Bh(262)

Characteristics: They show great similarities within a given period and group

The last electrons are added to the d orbital

112

Uub(277)

64

Gd

157.25

65

Tb

158.92

66

Dy

162.5

67

Ho

164.93

68

Er

167.26

69

Tm

168.93

58

Ce

140.12

59

Pr

140.9

60

Nd

144.2

61

Pm

(147)

62

Sm

150.35

63

Eu

151.96

70

Yb

173.04

71

Lu

174.97

Characteristics:• Electrons fill the 4f orbital

• These elements decrease in size, going from left to right

96

Cm

(247)

97

Bk

(247)

98

Cf

(252)

99

Es

(254)

100

Fm

(257)

101

Md

(257)

90

Th

232.03

91

Pa

(231)

92

U

238.0

93

Np

(237)

94

Pu

(234)

95

Am

(243)

102

No

(255)

103

Lr

(256)

Characteristics:• Members of the transitions

metals• Electrons fill the 5f orbital

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Alk

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Alk

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Transition Metals

Metals

Non-M

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Halo

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Nob

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Actinide Series

Lanthanide Series

Trends in the Periodic Table

When studying the periodic table one can tell many things about an element just by its location on the table. These trends help

scientists identify new elements and understand why an element has different

properties.

Atomic Radius

• Atomic radius within a group increases as one moves vertically down the periodic table.

• Atomic radius within a period decreases as one moves horizontally right across the periodic table.

Atomic Radius pattern

Where would you find the element with the a) largest radius b) smallest radius?

a) Bottom, left-hand side b) Top, right-hand side

Ionization Energy(the energy required to remove an electron from an element)

• The energy required for elements within a group decreases as one moves vertically down the periodic table.

• The energy required for elements within a period increases as one moves horizontally right across the periodic table.

Ionization Energy pattern

Where would you find the element with the a) largest ionization energy b) smallest ionization energy?

a), Top, right-hand side b) bottom left-hand side

Shielding Effect

• A decrease in the attraction of the outer electrons (valence electrons) to the positively-charged nucleus.

• Increases as one moves vertically down the periodic table.

• It remains constant as you move right across the periodic table because the electrons aren’t being added to a new energy level.

Shielding Effect pattern

As you move down the periodic table there are more electrons inside an element. This creates less of an attraction to the valence electrons. (the electrons in the lower energy levels are taking up too much of the nucleus’ attention.)

Electronegativity (EN)

• How strong the bonds are within the compound.

• Decreases as you move down the periodic table because the energy levels are growing.

• Increases as you move right across the periodic table because more p+ are added to the nucleus allowing for more electrons.

Electronegativity pattern

F is the most electronegative element at 4.0 and Francium is the least at 0.7.

Electron affinity

• A measure of the energy change that occurs as an electron is added to an atom

• Has the same trends as electronegativity for the same reasons (what you wrote on the previous slide).

Electron Affinity pattern

Common Elements & Their Symbols

Element Symbol Origin UsesAluminum Al Latin, alumen Soda cans

Arsenic As Latin, arsenicum Poisons

Calcium Ca Latin, calx Cement, lime

Chlorine Cl Greek, chloros Pools

Hydrogen H Greek, hydro Rockets

Neon Ne Green, neos Advertising signs

Oxygen O Greek, oxys Breathing

Sulfur S Sanskrit, sulvere Car tires

Zinc Zn German, zink nails

Common Elements with Unique Symbols

Element Symbol Origin UsesAntimony Sb Latin, stibium batteries

Copper Cu Latin, cuprum Wire

Gold Au Latin, aurum Jewelry

Iron Fe Latin, ferrum Steel

Lead Pb Latin, plumbum Car batteries

Mercury Hg Ancient, hydrargyrum

Thermometers

Potassium K Latin, kalium Fertilizers

Silber Ag Latin, argentum Coins

Sodium Na Latin, natrium salt

Can atoms be counted or measured?

Types of Measurements

• Mole - base comparison of all types of elements

• Amu - measurement of one element/atom

• Grams - measurement of a mole of atoms

Avogadro’s Number

• The number of particles in 1 mole (mol) of a pure substance.

• 6.022 x 1023

• Used to calculate the number of atoms(molecules) in a mole or the number of moles created by the atoms.

Atomic Mass (Mass Number)

The average of all of the masses of the naturally occurring isotopes of an element.

The mass number is the rounded atomic mass. It is the number of protons and neutrons found in an atom.

1

H

1.01

Atomic mass is expressed in Atomic Mass Units (amu)

• The mass number is the mass of both the protons and neutrons, not the total mass.

• Scientists developed a unit to compare all atoms.

• 1 amu = 1.66 x 10-24 g (1/12th the mass of Carbon-12)

Average Atomic Mass on the PT

• When you read the mass on the PT, the units are amu

• Cu = 63.55 amu• These average atomic masses are the

average of the atomic masses of the isotopes occurring in nature.

• Amu when single atom; grams when larger amounts of materials

How to calculate the amu

• Scientists use the % of existence of isotopes multiplied by the mass all totaled to get the mass.

Ex: Cu-63 exists 69.17% of the time yielding a mass of 62.94 amu and Cu-65 exists the other 30.83% of the time with a mass of 64.93 amu. Together they create the amu of Cu.

= (0.6917 x 62.94 amu) + (0.3083 x 64.93 amu) = 63.55 amu

Practice

• Si exists 92.21% of the time giving a mass of 27.98 amu, 4.70% of the time giving a mass of 28.98 amu and 3.09% of the time with a mass of 29.97. What is the amu?

=(0.9221 x 27.98 amu) + (0.0470 x 28.98 amu) + (0.0309 x 29.97 amu) =

=25.80 amu + 1.36 amu + 0.9261 amu = 28.09 amu

(REMEMBER SIG FIGS!!!!!)

Calculations using Factor Labeling

• If we have 5 mol of O, then we have ___ atoms of O.

5.00mol1

×6.022x1023 atoms

1mol=3.01x1024atoms

Practice

• How many atoms are in 3.20 mol of Cl?

3.20mol1

x6.022x1023atoms

1mol=1.93x1024atoms

Another try

• If you have 1.23 x 1025 atoms of Br, how many moles do you have?

1.23x1025atoms1

x1mol

6.022x1023atoms=20.4mol

Relating moles to molar mass (g)

• Molar mass is the amu’s written as grams.

• Ex: Cu has an atomic mass of 63.55 amu and a molar mass of 63.55 g.

• 1 mol = molar mass

• 1 mol = 63.55 g (for Cu)

Sample Problem

• Determine the mass in grams of 3.50 moles of Cu.

3.50molCu1

x63.55g1mol

=222gCu

Practice

• Find the mass in grams of 7.55 mol of Si.

7.55mol1

x28.09gSi

1mol=212gSi

Another Try

• If you have 35.4 g of MgCl2, how many moles do you have? (MgCl2=1 Mg & 2 Cl)

€

35.4gMgCl21

x1mol

95.21gMgCl2= 0.372molMgCl2