Ionization Energy of Chemical Elements

Periodic Table of Elements - ionization energy
1
H

Hydrogen

13.5984 eV

2
He

Helium

24.5874 eV

3
Li

Lithium

5.3917 eV

4
Be

Beryllium

9.3226 eV

5
B

Boron

8.298 eV

6
C

Carbon

11.2603 eV

7
N

Nitrogen

14.5341 eV

8
O

Oxygen

13.6181 eV

9
F

Fluorine

17.4228 eV

10
Ne

Neon

21.5645 eV

11
Na

Sodium

5.1391 eV

12
Mg

Magnesium

7.6462 eV

13
Al

Aluminium

5.9858 eV

14
Si

Silicon

8.1517 eV

15
P

Phosphorus

10.4867 eV

16
S

Sulfur

10.36 eV

17
Cl

Chlorine

12.9676 eV

18
Ar

Argon

15.7596 eV

19
K

Potassium

4.3407 eV

20
Ca

Calcium

6.1132 eV

21
Sc

Scandium

6.5614 eV

22
Ti

Titanium

6.8282 eV

23
V

Vanadium

6.7463 eV

24
Cr

Chromium

6.7666 eV

25
Mn

Manganese

7.434 eV

26
Fe

Iron

7.9024 eV

27
Co

Cobalt

7.881 eV

28
Ni

Nickel

7.6398 eV

29
Cu

Copper

7.7264 eV

30
Zn

Zinc

9.3941 eV

31
Ga

Gallium

5.9993 eV

32
Ge

Germanium

7.9 eV

33
As

Arsenic

9.8152 eV

34
Se

Selenium

9.7524 eV

35
Br

Bromine

11.8138 eV

36
Kr

Krypton

13.9996 eV

37
Rb

Rubidium

4.1771 eV

38
Sr

Strontium

5.6948 eV

39
Y

Yttrium

6.217 eV

40
Zr

Zirconium

6.6339 eV

41
Nb

Niobium

6.7589 eV

42
Mo

Molybdenum

7.0924 eV

43
Tc

Technetium

7.28 eV

44
Ru

Ruthenium

7.3605 eV

45
Rh

Rhodium

7.4589 eV

46
Pd

Palladium

8.3369 eV

47
Ag

Silver

7.5762 eV

48
Cd

Cadmium

8.9937 eV

49
In

Indium

5.7864 eV

50
Sn

Tin

7.3438 eV

51
Sb

Antimony

8.64 eV

52
Te

Tellurium

9.0098 eV

53
I

Iodine

10.4513 eV

54
Xe

Xenon

12.1299 eV

55
Cs

Caesium

3.8939 eV

56
Ba

Barium

5.2117 eV

57-71

 

Lanthanoids

 

72
Hf

Hafnium

6.8251 eV

73
Ta

Tantalum

7.89 eV

74
W

Tungsten

7.98 eV

75
Re

Rhenium

7.88 eV

76
Os

Osmium

8.7 eV

77
Ir

Iridium

9.1 eV

78
Pt

Platinum

9 eV

79
Au

Gold

9.2257 eV

80
Hg

Mercury

10.4375 eV

81
Tl

Thallium

6.1083 eV

82
Pb

Lead

7.4167 eV

83
Bi

Bismuth

7.289 eV

84
Po

Polonium

8.4167 eV

85
At

Astatine

9.5 eV

86
Rn

Radon

10.7485 eV

87
Fr

Francium

3.94 eV

88
Ra

Radium

5.2789 eV

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

5.577 eV

58
Ce

Cerium

5.5387 eV

59
Pr

Praseodymium

5.464 eV

60
Nd

Neodymium

5.525 eV

61
Pm

Promethium

5.55 eV

62
Sm

Samarium

5.6437 eV

63
Eu

Europium

5.6704 eV

64
Gd

Gadolinium

6.15 eV

65
Tb

Terbium

5.8939 eV

66
Dy

Dysprosium

5.9389 eV

67
Ho

Holmium

6.0216 eV

68
Er

Erbium

6.1078 eV

69
Tm

Thulium

6.1843 eV

70
Yb

Ytterbium

6.2542 eV

71
Lu

Lutetium

5.4259 eV

89
Ac

Actinium

5.17 eV

90
Th

Thorium

6.08 eV

91
Pa

Protactinium

5.89 eV

92
U

Uranium

6.1941 eV

93
Np

Neptunium

6.2657 eV

94
Pu

Plutonium

6.06 eV

95
Am

Americium

5.9933 eV

96
Cm

Curium

6.02 eV

97
Bk

Berkelium

6.23 eV

98
Cf

Californium

6.3 eV

99
Es

Einsteinium

6.42 eV

100
Fm

Fermium

6.5 eV

101
Md

Mendelevium

6.58 eV

102
No

Nobelium

6.65 eV

103
Lr

Lawrencium

 

Ionization Energy of Chemical Elements

Ionization energy, also called ionization potential, is the energy necessary to remove an electron from the neutral atom.

X + energy → X+ + e

where X is any atom or molecule capable of being ionized, X+ is that atom or molecule with an electron removed (positive ion), and e is the removed electron.

For example, a carbon atom, for example, requires the following ionization energy to remove the outermost electron.

C + IE → C+ + e        IE = 11.2603 eV

The ionization energy associated with removal of the first electron is most commonly used. The nth ionization energy refers to the amount of energy required to remove an electron from the species with a charge of (n-1).

1st ionization energy

X → X+ + e

2nd ionization energy

X+ → X2+ + e

3rd ionization energy

X2+ → X3+ + e

Ionization Energy for different Elements

There is an ionization energy for each successive electron removed. The electrons that circle the nucleus move in fairly well-defined orbits. Some of these electrons are more tightly bound in the atom than others. For example, only 7.38 eV is required to remove the outermost electron from a lead atom, while 88,000 eV is required to remove the innermost electron. Helps to understand reactivity of elements (especially metals, which lose electrons).

ionization energy - periodic tableIn general, the ionization energy increases moving up a group and moving left to right across a period. Ionization energy is is related with electronegativity and electron affinity. Electrons with low ionization energies have low electronegativities because their nuclei do not exert a strong attractive force on electrons. Elements with high ionization energies have high electronegativities due to the strong pull exerted by the positive nucleus on the negative electrons. Therefore the electronegativity is greatest at the top-right of the periodic table and decreases toward the bottom-left. Moreover:

  • Ionization energy is lowest for the alkali metals which have a single electron outside a closed shell.
  • Ionization energy increases across a row on the periodic maximum for the noble gases which have closed shells.

For example, sodium requires only 496 kJ/mol or 5.14 eV/atom to ionize it. On the other hand neon, the noble gas, immediately preceding it in the periodic table, requires 2081 kJ/mol or 21.56 eV/atom.

Ionization energy

Properties of other elements