L'énergie de première ionisation (de M à M+), est l'énergie nécessaire pour supprimer le premier électron de l'atome neutre : M+ symbolisant le premier cation.

On observe sans surprise que les éléments des colonnes les plus à droite nécessitent une énergie plus importante, leur couche électronique la plus haute étant saturée : l’Hélium étant l’élément le plus difficile à ioniser. A contrario, on observe que les éléments chimiques des premières colonnes sont très facilement ionisables en raison de leurs couches électroniques insaturées. Il s’agit donc une fois de plus d’une propriété périodique.

1.01
1
H
Hydrogène
1312 kJ/mol
1 18
1
1 H 1312 kJ/mol
 2 13 14 15 16 17
2 He 2372.3 kJ/mol
2
3 Li 520.2 kJ/mol
4 Be 899.5 kJ/mol
5 B 800.6 kJ/mol
6 C 1086.5 kJ/mol
7 N 1402.3 kJ/mol
8 O 1313.9 kJ/mol
9 F 1681 kJ/mol
10 Ne 2080.7 kJ/mol
3
11 Na 495.8 kJ/mol
12 Mg 737.7 kJ/mol
 3 4 5 6 7 8 9 10 11 12
13 Al 577.5 kJ/mol
14 Si 786.5 kJ/mol
15 P 1011.8 kJ/mol
16 S 999.6 kJ/mol
17 Cl 1251.2 kJ/mol
18 Ar 1520.6 kJ/mol
4
19 K 418.8 kJ/mol
20 Ca 589.8 kJ/mol
21 Sc 633.1 kJ/mol
22 Ti 658.8 kJ/mol
23 V 650.9 kJ/mol
24 Cr 652.9 kJ/mol
25 Mn 717.3 kJ/mol
26 Fe 762.5 kJ/mol
27 Co 760.4 kJ/mol
28 Ni 737.1 kJ/mol
29 Cu 745.5 kJ/mol
30 Zn 906.4 kJ/mol
31 Ga 578.8 kJ/mol
32 Ge 762 kJ/mol
33 As 947 kJ/mol
34 Se 941 kJ/mol
35 Br 1139.9 kJ/mol
36 Kr 1350.8 kJ/mol
5
37 Rb 403 kJ/mol
38 Sr 549.5 kJ/mol
39 Y 600 kJ/mol
40 Zr 640.1 kJ/mol
41 Nb 652.1 kJ/mol
42 Mo 684.3 kJ/mol
43 Tc 702 kJ/mol
44 Ru 710.2 kJ/mol
45 Rh 719.7 kJ/mol
46 Pd 804.4 kJ/mol
47 Ag 731 kJ/mol
48 Cd 867.8 kJ/mol
49 In 558.3 kJ/mol
50 Sn 708.6 kJ/mol
51 Sb 834 kJ/mol
52 Te 869.3 kJ/mol
53 I 1008.4 kJ/mol
54 Xe 1170.4 kJ/mol
6
55 Cs 375.7 kJ/mol
56 Ba 502.9 kJ/mol
 L
71 Lu 523.5 kJ/mol
72 Hf 658.5 kJ/mol
73 Ta 761 kJ/mol
74 W 770 kJ/mol
75 Re 760 kJ/mol
76 Os 840 kJ/mol
77 Ir 880 kJ/mol
78 Pt 870 kJ/mol
79 Au 890.1 kJ/mol
80 Hg 1007.1 kJ/mol
81 Tl 589.4 kJ/mol
82 Pb 715.6 kJ/mol
83 Bi 703 kJ/mol
84 Po 812.1 kJ/mol
85 At 887.7 kJ/mol
86 Rn 1037 kJ/mol
7
87 Fr 380 kJ/mol
88 Ra 509.3 kJ/mol
 A
103 Lr 470 kJ/mol
L
57 La 538.1 kJ/mol
58 Ce 534.4 kJ/mol
59 Pr 527 kJ/mol
60 Nd 533.1 kJ/mol
61 Pm 540 kJ/mol
62 Sm 544.5 kJ/mol
63 Eu 547.1 kJ/mol
64 Gd 593.4 kJ/mol
65 Tb 565.8 kJ/mol
66 Dy 573 kJ/mol
67 Ho 581 kJ/mol
68 Er 589.3 kJ/mol
69 Tm 596.7 kJ/mol
70 Yb 603.4 kJ/mol
A
89 Ac 499 kJ/mol
90 Th 587 kJ/mol
91 Pa 568 kJ/mol
92 U 597.6 kJ/mol
93 Np 604.5 kJ/mol
94 Pu 584.7 kJ/mol
95 Am 578 kJ/mol
96 Cm 581 kJ/mol
97 Bk 601 kJ/mol
98 Cf 608 kJ/mol
99 Es 619 kJ/mol
100 Fm 627 kJ/mol
101 Md 635 kJ/mol
102 No 642 kJ/mol
Energie d'ionisation de M à M+
  • ?
  • 0
  • 237
  • 474
  • 711
  • 948
  • 1186
  • 1423
  • 1660
  • 1897
  • 2134
  • 2372
Z Symbole Nom Energie d'ionisation de M à M+
1 H Hydrogène
 1312 kJ/mol
2 He Hélium
 2372.3 kJ/mol
3 Li Lithium
 520.2 kJ/mol
4 Be Béryllium
 899.5 kJ/mol
5 B Bore
 800.6 kJ/mol
6 C Carbone
 1086.5 kJ/mol
7 N Azote
 1402.3 kJ/mol
8 O Oxygène
 1313.9 kJ/mol
9 F Fluor
 1681 kJ/mol
10 Ne Néon
 2080.7 kJ/mol
11 Na Sodium
 495.8 kJ/mol
12 Mg Magnésium
 737.7 kJ/mol
13 Al Aluminium
 577.5 kJ/mol
14 Si Silicium
 786.5 kJ/mol
15 P Phosphore
 1011.8 kJ/mol
16 S Soufre
 999.6 kJ/mol
17 Cl Chlore
 1251.2 kJ/mol
18 Ar Argon
 1520.6 kJ/mol
19 K Potassium
 418.8 kJ/mol
20 Ca Calcium
 589.8 kJ/mol
21 Sc Scandium
 633.1 kJ/mol
22 Ti Titane
 658.8 kJ/mol
23 V Vanadium
 650.9 kJ/mol
24 Cr Chrome
 652.9 kJ/mol
25 Mn Manganèse
 717.3 kJ/mol
26 Fe Fer
 762.5 kJ/mol
27 Co Cobalt
 760.4 kJ/mol
28 Ni Nickel
 737.1 kJ/mol
29 Cu Cuivre
 745.5 kJ/mol
30 Zn Zinc
 906.4 kJ/mol
31 Ga Gallium
 578.8 kJ/mol
32 Ge Germanium
 762 kJ/mol
33 As Arsenic
 947 kJ/mol
34 Se Sélénium
 941 kJ/mol
35 Br Brome
 1139.9 kJ/mol
36 Kr Krypton
 1350.8 kJ/mol
37 Rb Rubidium
 403 kJ/mol
38 Sr Strontium
 549.5 kJ/mol
39 Y Yttrium
 600 kJ/mol
40 Zr Zirconium
 640.1 kJ/mol
41 Nb Niobium
 652.1 kJ/mol
42 Mo Molybdène
 684.3 kJ/mol
43 Tc Technétium
 702 kJ/mol
44 Ru Ruthénium
 710.2 kJ/mol
45 Rh Rhodium
 719.7 kJ/mol
46 Pd Palladium
 804.4 kJ/mol
47 Ag Argent
 731 kJ/mol
48 Cd Cadmium
 867.8 kJ/mol
49 In Indium
 558.3 kJ/mol
50 Sn Etain
 708.6 kJ/mol
51 Sb Antimoine
 834 kJ/mol
52 Te Tellure
 869.3 kJ/mol
53 I Iode
 1008.4 kJ/mol
54 Xe Xénon
 1170.4 kJ/mol
55 Cs Césium
 375.7 kJ/mol
56 Ba Baryum
 502.9 kJ/mol
57 La Lanthane
 538.1 kJ/mol
58 Ce Cérium
 534.4 kJ/mol
59 Pr Praséodyme
 527 kJ/mol
60 Nd Néodyme
 533.1 kJ/mol
61 Pm Prométhium
 540 kJ/mol
62 Sm Samarium
 544.5 kJ/mol
63 Eu Europium
 547.1 kJ/mol
64 Gd Gadolinum
 593.4 kJ/mol
65 Tb Terbium
 565.8 kJ/mol
66 Dy Dysprosium
 573 kJ/mol
67 Ho Holmium
 581 kJ/mol
68 Er Erbium
 589.3 kJ/mol
69 Tm Thulium
 596.7 kJ/mol
70 Yb Ytterbium
 603.4 kJ/mol
71 Lu Lutécium
 523.5 kJ/mol
72 Hf Hafnium
 658.5 kJ/mol
73 Ta Tantale
 761 kJ/mol
74 W Tungstène
 770 kJ/mol
75 Re Rhénium
 760 kJ/mol
76 Os Osmium
 840 kJ/mol
77 Ir Iridium
 880 kJ/mol
78 Pt Platine
 870 kJ/mol
79 Au Or
 890.1 kJ/mol
80 Hg Mercure
 1007.1 kJ/mol
81 Tl Thallium
 589.4 kJ/mol
82 Pb Plomb
 715.6 kJ/mol
83 Bi Bismuth
 703 kJ/mol
84 Po Polonium
 812.1 kJ/mol
85 At Astate
 887.7 kJ/mol
86 Rn Radon
 1037 kJ/mol
87 Fr Francium
 380 kJ/mol
88 Ra Radium
 509.3 kJ/mol
89 Ac Actinium
 499 kJ/mol
90 Th Thorium
 587 kJ/mol
91 Pa Protactinium
 568 kJ/mol
92 U Uranium
 597.6 kJ/mol
93 Np Neptunium
 604.5 kJ/mol
94 Pu Plutonium
 584.7 kJ/mol
95 Am Américium
 578 kJ/mol
96 Cm Curium
 581 kJ/mol
97 Bk Berkélium
 601 kJ/mol
98 Cf Californium
 608 kJ/mol
99 Es Einsteinium
 619 kJ/mol
100 Fm Fermium
 627 kJ/mol
101 Md Mendélévium
 635 kJ/mol
102 No Nobélium
 642 kJ/mol
103 Lr Lawrencium
 470 kJ/mol