A Visual Encyclopedia of the Periodic Table

15

Introduction

Tl

81

204.

KEY

Hydrogen The Boron Group

Alkali Metals The Carbon Group

Alkaline Earth Metals The Nitrogen Group

Transition Metals The Oxygen Group

Lanthanides The Halogen Group

Actinides Noble Gases

Periods run from

left to right.

Groups run from

top to bottom.

Ga

31

In

49

Al

13

Dy

66

Nh

113

Cf

98

Reading the table

The periodic table was

developed by the Russian

chemist Dmitri Mendeleev in

1869. Others had tried before,
      but his table was periodic,
      or repeating, because the
      characteristics of elements
      follow a pattern. The table was
      incomplete as some elements
      had not yet been discovered.
      However, Mendeleev predicted
      the positions of the missing
      elements, and was proved right
      when they were finally isolated
      many years later.

DMITRI MENDELEEV

114.

26.

284

162.

(251)

69.

B

5

10.

Ge

32

C

6

Sn

50

Si

14

Pb

82

Ho

67

Fl

114

Es

99

118.

28.

207.

289

164.

(252)

72.

12.

As

33

N

7

Sb

51

P

15

Bi

83

Er

68

Mc

115

Fm

100

121.

30.

208.

288

167.

(257)

74.

14.

Se

34

O

8

Te

52

S

16

Po

84

Tm

69

Lv

116

Md

101

127.

32.

(209)

293

168.

(258)

78.

15.

Br

35

F

9

I

53

Cl

17

At

85

Yb

70

Ts

117

No

102

126.

35.

(210)

294

173.

(259)

79.

18.

Kr

36

Ne

10

He

2

Xe

54

Ar

18

Rn

86

Lu

71

Og

118

Lr

103

131.

39.

(222)

294

174.

(262)

83.

20.

4.

This group contains

the noble gases, which

never form bonds with other

elements, and are unreactive.

Elements of this group

are semi-metals (elements

with the properties of

metals and non-metals):

they are shiny like metals

but crumble easily

like non-metals.

Element symbol

Every element has a unique symbol of one or two

letters. These symbols ensure that scientists who

speak different languages do not get confused while

describing the same element.

Periods

Elements in the same period, or row, have the same

number of electron shells in their atoms. So elements

in period one have one electron shell, while those in

period six have six electron shells.

Groups

Members of a group, or column, all

have the same number of electrons

in their outermost shell. For example,

group one elements have one outer

electron, while group eight elements

have eight outer electrons.

Li

3

6. 
   

The atomic number is the number of protons

in the nucleus of this element’s atoms.

The first letter of a symbol is always

a capital, but the second is lower case.

The atomic mass number is the average of all the

atoms of the element. It is not a whole number

because there are different isotopes (forms) of each

element, each with a different number of neutrons.

014-015_Periodic_Table.indd 15 12/12/16 5:37 pm