Electronic Structure of Metals and Atomic Parameters - Fundamental QSARs for Metal Ions - page 24

Group
Period

IA IIA 3

IIIB

4
IVB

VB VIB VIIB 8

VIIIB

9
VIIIB

10
VIIIB

11
IB

12
IIB

13
IIIA

14
IVA

1 VA 16

VIA

17
VIIA

18
VIIIA

2
He

1

1
H

2

3
Li

4
Be

5
B

6
C

7
N

8
O

9
F

10
Ne

3

11
Na

12
Mg

13
Al

14
Si

15
P

16
S

17
Cl

18
Ar

4

20
Ca

21
Sc

22
Ti

23
V

24
Cr

25
Mn

26
Fe

27
Co

28
Ni

29
Cu

30
Zn

31
Ga

32
Ge

33
As

34
Se

35
Br

36
Kr

5

37
Rb

38
Sr

39
Y

40
Zr

41
Nb

42
Mo

43
Tc

44
Ru

45
Rh

46
Pd

47
Ag

48
Cd

49
In

50
Sn

51
Sb

52
Te

53
I

54
Xe

6

55
Cs

56
Ba

72
Hf

73
Ta

74
W

75
Re

76
Os

77
Ir

78
Pt

79
Au

80
Hg

81
Tl

82
Pb

83
Bi

84
Po

85
At

86
Rn

*

7

87
Fr

88
Ra

104
Rf

105
Db

106
Sg

107
Bh

108
Hs

109
Mt

110
Ds

111
Rg

112
Cn

**

58
Ce

59
Pr

60
Nd

61
Pm

62
Sm

63
Eu

57
La

64
Gd

65
Tb

66
Dy

67
Ho

68
Er

69
Tm

70
Yb

71
Lu

*Lanthanides

89
Ac

90
' 9 Pa

92
U

93
Np

94
Pu

95
Am

96
Cm

97
Bk

98
Cf

99
Es

100
Fm

101
Md

102
No

103
Lr

**Actinides

Notes:
Metals: alkali metals (group 1 elements), alkaline earth metals (group 2 elements), transition metals
(groups 3 to 11), post-transition metals (group 12 elements and Al, Ga, In, Tl, Sn, Pb, Bi), lanthanides
and actinides
Metalloids: B, Si, Ge, As, Sb, Se, Te, sometimes Po is also added to the list
Non-metals: H, C, N, P, O, S, halogens (group 17 elements) and the noble gases (group 18 elements)

FIGURE 2.1 The periodic table of the elements and the classification of chemical elements
as metals, nonmetals, and metalloids.

have intermediate properties between metals and nonmetals are called metalloids
(Figure 2.1). The main characteristics that separate metals, nonmetals, and metal-
loids are presented in Table 2.1 .
The metallic character is a result of a particular type of chemical bond (the metallic
bonding) that can be found in the solid state and in the liquid (melted) state of a
chemical substance, but disappears in the gaseous state.
The metallic bonding holds together the atoms of a metal and determines the
formation of the metal crystal structures. All valence electrons of the atoms in the
metal form a common electronic cloud in the crystal lattice. In the crystal struc-
tures, the metal atoms usually have the coordination number 12 or 8 with lower
coordination numbers being found in less-compact crystal structures (In, white Sn,
Sb, Bi).
Metals have few electrons in their valence shells, and these electrons are loosely
bound; therefore, metals have low ionization energy and a low electronegativity.
Within the periodic table groups, the metallic character is increasingly down-
ward, due to the increase of the atomic radius; therefore, the longer the distance
between the nucleus and the valence electrons, the less electrical attraction can
be manifested between them. Also, within the periodic table periods, the metallic
character decreases from left to right, following the decrease of the atomic radius.
An electron situated near a positively charged nucleus is more difficult to remove;
therefore, such atoms tend to accept electrons to fill the valence shell rather than
lose them.
The density of the metals varies between 0.53 g/cm 3 for lithium and 22.6 g/cm 3
for osmium; most metals have values of 5-9 g/cm 3 . In general, the higher density of