Electron Affinity of Chemical Elements

Periodic Table of Elements - electron affinity
1
H

Hydrogen

72.8 kJ/mol

2
He

Helium

0 kJ/mol

3
Li

Lithium

59.6 kJ/mol

4
Be

Beryllium

0 kJ/mol

5
B

Boron

26.7 kJ/mol

6
C

Carbon

153.9 kJ/mol

7
N

Nitrogen

7 kJ/mol

8
O

Oxygen

141 kJ/mol

9
F

Fluorine

328 kJ/mol

10
Ne

Neon

0 kJ/mol

11
Na

Sodium

52.8 kJ/mol

12
Mg

Magnesium

0 kJ/mol

13
Al

Aluminium

42.5 kJ/mol

14
Si

Silicon

133.6 kJ/mol

15
P

Phosphorus

72 kJ/mol

16
S

Sulfur

200 kJ/mol

17
Cl

Chlorine

349 kJ/mol

18
Ar

Argon

0 kJ/mol

19
K

Potassium

48.4 kJ/mol

20
Ca

Calcium

2.4 kJ/mol

21
Sc

Scandium

18.1 kJ/mol

22
Ti

Titanium

7.6 kJ/mol

23
V

Vanadium

50.6 kJ/mol

24
Cr

Chromium

64.3 kJ/mol

25
Mn

Manganese

0 kJ/mol

26
Fe

Iron

15.7 kJ/mol

27
Co

Cobalt

63.7 kJ/mol

28
Ni

Nickel

112 kJ/mol

29
Cu

Copper

118.4 kJ/mol

30
Zn

Zinc

0 kJ/mol

31
Ga

Gallium

28.9 kJ/mol

32
Ge

Germanium

119 kJ/mol

33
As

Arsenic

78 kJ/mol

34
Se

Selenium

195 kJ/mol

35
Br

Bromine

324.6 kJ/mol

36
Kr

Krypton

0 kJ/mol

37
Rb

Rubidium

46.9 kJ/mol

38
Sr

Strontium

5 kJ/mol

39
Y

Yttrium

29.6 kJ/mol

40
Zr

Zirconium

41.1 kJ/mol

41
Nb

Niobium

86.1 kJ/mol

42
Mo

Molybdenum

71.9 kJ/mol

43
Tc

Technetium

53 kJ/mol

44
Ru

Ruthenium

101.3 kJ/mol

45
Rh

Rhodium

109.7 kJ/mol

46
Pd

Palladium

53.7 kJ/mol

47
Ag

Silver

125.6 kJ/mol

48
Cd

Cadmium

0 kJ/mol

49
In

Indium

28.9 kJ/mol

50
Sn

Tin

107.3 kJ/mol

51
Sb

Antimony

103.2 kJ/mol

52
Te

Tellurium

190.2 kJ/mol

53
I

Iodine

295.2 kJ/mol

54
Xe

Xenon

0 kJ/mol

55
Cs

Caesium

45.5 kJ/mol

56
Ba

Barium

13.9 kJ/mol

57-71

 

Lanthanoids

 

72
Hf

Hafnium

0 kJ/mol

73
Ta

Tantalum

31 kJ/mol

74
W

Tungsten

78.6 kJ/mol

75
Re

Rhenium

14.5 kJ/mol

76
Os

Osmium

106.1 kJ/mol

77
Ir

Iridium

151 kJ/mol

78
Pt

Platinum

205.3 kJ/mol

79
Au

Gold

222.8 kJ/mol

80
Hg

Mercury

0 kJ/mol

81
Tl

Thallium

19.2 kJ/mol

82
Pb

Lead

35.1 kJ/mol

83
Bi

Bismuth

91.2 kJ/mol

84
Po

Polonium

183.3 kJ/mol

85
At

Astatine

270.1 kJ/mol

86
Rn

Radon

0 kJ/mol

87
Fr

Francium

 

88
Ra

Radium

 

89-103

 

Actinoids

 

104
Rf

Rutherfordium

 

105
Db

Dubnium

 

106
Sg

Seaborgium

 

107
Bh

Bohrium

 

108
Hs

Hassium

 

109
Mt

Meitnerium

 

110
Ds

Darmstadtium

 

111
Rg

Roentgenium

 

112
Cn

Copernicium

 

113
Nh

Nihonium

 

114
Fl

Flerovium

 

115
Mc

Moscovium

 

116
Lv

Livermorium

 

117
Ts

Tennessine

 

118
Og

Oganesson

 

57
La

Lanthanum

48 kJ/mol

58
Ce

Cerium

50 kJ/mol

59
Pr

Praseodymium

50 kJ/mol

60
Nd

Neodymium

50 kJ/mol

61
Pm

Promethium

50 kJ/mol

62
Sm

Samarium

50 kJ/mol

63
Eu

Europium

50 kJ/mol

64
Gd

Gadolinium

50 kJ/mol

65
Tb

Terbium

50 kJ/mol

66
Dy

Dysprosium

50 kJ/mol

67
Ho

Holmium

50 kJ/mol

68
Er

Erbium

50 kJ/mol

69
Tm

Thulium

50 kJ/mol

70
Yb

Ytterbium

50 kJ/mol

71
Lu

Lutetium

50 kJ/mol

89
Ac

Actinium

 

90
Th

Thorium

 

91
Pa

Protactinium

 

92
U

Uranium

 

93
Np

Neptunium

 

94
Pu

Plutonium

 

95
Am

Americium

 

96
Cm

Curium

 

97
Bk

Berkelium

 

98
Cf

Californium

 

99
Es

Einsteinium

 

100
Fm

Fermium

 

101
Md

Mendelevium

 

102
No

Nobelium

 

103
Lr

Lawrencium

 

Electron Affinity of Chemical Elements

In chemistry and atomic physics, the electron affinity of an atom or molecule is defined as:

the change in energy (in kJ/mole) of a neutral atom or molecule (in the gaseous phase) when an electron is added to the atom to form a negative ion.

X + e → X + energy        Affinity = – ∆H

In other words, it can be expressed as the neutral atom’s likelihood of gaining an electron. Note that, ionization energies measure the tendency of a neutral atom to resist the loss of electrons. Electron affinities are more difficult to measure than ionization energies.

For example, electron affinity of carbon is 153.9 kJ/mol. An atom of carbon in the gas phase, for example, gives off energy when it gains an electron to form an ion of carbon.

C + e → C        – ∆H = Affinity = 153.9 kJ/mol

To use electron affinities properly, it is essential to keep track of sign. When an electron is added to a neutral atom, energy is released. This affinity is known as the first electron affinity and these energies are negative. By convention, the negative sign shows a release of energy. However, more energy is required to add an electron to a negative ion which overwhelms any the release of energy from the electron attachment process. This affinity is known as the second electron affinity and these energies are positive.

electron affinity - periodic tableElectron affinity can be either positive or negative value. The greater the negative value, the more stable the anion is. Although affinity varies greatly across the periodic table, some patterns emerge. Generally, the elements on the right side of the periodic table will have large negative electron affinity. The electron affinities will become less negative as you go from the top to the bottom of the periodic table. However, nitrogen, oxygen, and fluorine do not follow this trend. Moreover, nonmetals have more positive affinity than metals. Atoms whose anions are more stable than neutral atoms have a greater affinity. Chlorine most strongly attracts extra electrons, while neon most weakly attracts an extra electron.

Affinities of Non metals vs. Affinities of Metals

  • Metals: Metals like to lose valence electrons to form cations to have a fully stable shell. The electron affinity of metals is lower than that of nonmetals. Mercury most weakly attracts an extra electron.
  • Nonmetals: Generally, nonmetals have more positive electron affinity than metals. Nonmetals like to gain electrons to form anions to have a fully stable electron shell. Chlorine most strongly attracts extra electrons. The electron affinities of the noble gases have not been conclusively measured, so they may or may not have slightly negative values.

 

Properties of other elements