Ionization energies

Successive energies required to remove electrons from a gaseous atom. Large jumps between successive steps indicate the start of a deeper shell.

Minimum 3.893906 eV Cesium

Maximum 24.587389 eV Helium

Average 7.921375 eV

Data available 109 of 118

Showing 118 of 118 elements

	Symbol	Name
1	H	Hydrogen	13.598434	—	—	—	—
2	He	Helium	24.587389	54.417765	—	—	—
3	Li	Lithium	5.391715	75.640096	122.454358	—	—
4	Be	Beryllium	9.322699	18.21115	153.896203	217.718583	—
5	B	Boron	8.298019	25.15483	37.93059	259.374377	340.226019
6	C	Carbon	11.260288	24.383143	47.88778	64.49352	392.090551
7	N	Nitrogen	14.53413	29.60125	47.4453	77.4735	97.8901
8	O	Oxygen	13.618055	35.12112	54.93554	77.4135	113.899
9	F	Fluorine	17.42282	34.97081	62.70798	87.175	114.249
10	Ne	Neon	21.564541	40.96297	63.4233	97.19	126.247
11	Na	Sodium	5.139077	47.28636	71.62	98.936	138.404
12	Mg	Magnesium	7.646236	15.035271	80.1436	109.2654	141.33
13	Al	Aluminum	5.985769	18.82855	28.447642	119.9924	153.8252
14	Si	Silicon	8.15168	16.34585	33.493	45.14179	166.767
15	P	Phosphorus	10.486686	19.76949	30.20264	51.44387	65.02511
16	S	Sulfur	10.360017	23.33788	34.86	47.222	72.5945
17	Cl	Chlorine	12.967633	23.81364	39.8	53.24	67.68
18	Ar	Argon	15.759612	27.62967	40.735	59.58	74.84
19	K	Potassium	4.340664	31.625	45.8031	60.917	82.66
20	Ca	Calcium	6.113155	11.871719	50.91316	67.2732	84.34
21	Sc	Scandium	6.56149	12.79977	24.756839	73.4894	91.95
22	Ti	Titanium	6.82812	13.5755	27.49171	43.26717	99.299
23	V	Vanadium	6.746187	14.634	29.3111	46.709	65.28165
24	Cr	Chromium	6.76651	16.486305	30.959	49.16	69.46
25	Mn	Manganese	7.434038	15.63999	33.668	51.21	72.41
26	Fe	Iron	7.902468	16.19921	30.651	54.91	75
27	Co	Cobalt	7.88101	17.0844	33.5	51.27	79.5
28	Ni	Nickel	7.639878	18.168838	35.187	54.92	76.06
29	Cu	Copper	7.72638	20.29239	36.841	57.38	79.8
30	Zn	Zinc	9.394197	17.96439	39.7233	59.573	82.6
31	Ga	Gallium	5.999302	20.51514	30.72576	63.241	86.01
32	Ge	Germanium	7.899435	15.93461	34.0576	45.7155	90.5
33	As	Arsenic	9.78855	18.5892	28.349	50.15	62.77
34	Se	Selenium	9.752368	21.196	31.697	42.947	68.3
35	Br	Bromine	11.81381	21.591	34.871	47.782	59.595
36	Kr	Krypton	13.999605	24.35984	35.838	50.85	64.69
37	Rb	Rubidium	4.177128	27.28954	39.247	52.2	68.436636
38	Sr	Strontium	5.694867	11.030276	42.88353	56.28	70.7
39	Y	Yttrium	6.21726	12.2236	20.52441	60.6072	75.35
40	Zr	Zirconium	6.634126	13.13	23.17	34.41836	80.348
41	Nb	Niobium	6.75885	14.32	25.04	37.611	50.5728
42	Mo	Molybdenum	7.09243	16.16	27.13	40.33	54.417
43	Tc	Technetium	7.11938	15.26	29.55	41.089193	57.143911
44	Ru	Ruthenium	7.3605	16.76	28.47	44.898787	59.048708
45	Rh	Rhodium	7.4589	18.08	31.06	41.905534	62.858302
46	Pd	Palladium	8.336839	19.43	32.93	45.987242	60.953505
47	Ag	Silver	7.576234	21.4844	34.8	48.980495	65.035213
48	Cd	Cadmium	8.99382	16.908313	37.468	50.885292	68.028465
49	In	Indium	5.786356	18.87041	28.04415	55.45	69.3
50	Sn	Tin	7.343918	14.63307	30.506	40.74	77.03
51	Sb	Antimony	8.608389	16.626	25.3235	43.804	55
52	Te	Tellurium	9.009808	18.6	27.84	37.4155	59.3
53	I	Iodine	10.451236	19.13126	29.57	40.357	51.52
54	Xe	Xenon	12.129844	20.975	31.05	42.2	54.1
55	Cs	Cesium	3.893906	23.15745	33.195	42.99399	56.055455
56	Ba	Barium	5.211665	10.003826	35.8438	47	57.960252
57	La	Lanthanum	5.5769	11.18496	19.1773	49.95	61.6
58	Ce	Cerium	5.5386	10.956	20.1974	36.906	65.55
59	Pr	Praseodymium	5.4702	10.631	21.6237	38.981	57.53
60	Nd	Neodymium	5.52475	10.783	22.09	40.6	60
61	Pm	Promethium	5.58187	10.938	22.44	41.17	61.7
62	Sm	Samarium	5.643722	11.078	23.55	41.64	62.7
63	Eu	Europium	5.670385	11.24	24.84	42.94	63.2
64	Gd	Gadolinium	6.1498	12.076	20.54	44.44	64.8
65	Tb	Terbium	5.8638	11.513	21.82	39.33	66.5
66	Dy	Dysprosium	5.939061	11.647	22.89	41.23	62.1
67	Ho	Holmium	6.0215	11.781	22.79	42.52	63.9
68	Er	Erbium	6.1077	11.916	22.7	42.42	65.1
69	Tm	Thulium	6.184402	12.065	23.66	42.41	65.4
70	Yb	Ytterbium	6.25416	12.179185	25.053	43.61	65.6
71	Lu	Lutetium	5.425871	14.13	20.9594	45.249	66.8
72	Hf	Hafnium	6.82507	14.607072	22.544633	33.37	68.37
73	Ta	Tantalum	7.549571	16.2	23.129678	34.830574	48.272
74	W	Tungsten	7.86403	16.37	26	38.2	51.6
75	Re	Rhenium	7.83352	16.6	26.939272	39.184396	51.973747
76	Os	Osmium	8.43823	17	25.034475	41.089193	54.967
77	Ir	Iridium	8.96702	17	28.027728	40.000737	57.143911
78	Pt	Platinum	8.95883	18.56	29.116183	42.99399	56.055455
79	Au	Gold	9.225554	20.203	29.932525	44.898787	60.137163
80	Hg	Mercury	10.437504	18.75688	34.49	48.55	61.2
81	Tl	Thallium	6.108287	20.4283	29.852	51.14	62.6
82	Pb	Lead	7.41668	15.032499	31.9373	42.33256	68.8
83	Bi	Bismuth	7.285516	16.703	25.57075	45.37	54.856
84	Po	Polonium	8.41807	19.3	27.3	35.91903	57.143911
85	At	Astatine	9.31751	17.88	26.58	39.65	50.39
86	Rn	Radon	10.7485	18.988105	29.4	37.007485	53.062203
87	Fr	Francium	4.072741	22.4	33.5	39.184396	50.06895
88	Ra	Radium	5.278424	10.14718	31.02098	41.089193	53.062203
89	Ac	Actinium	5.380235	11.75	17.436	44.8	54.967
90	Th	Thorium	6.3067	12.1	18.32	28.648	57.960252
91	Pa	Protactinium	5.89	11.9	18.6	30.9	44.272925
92	U	Uranium	6.19405	11.6	19.8	36.7	45.987242
93	Np	Neptunium	6.265608	11.5	19.7	33.8	47.892039
94	Pu	Plutonium	6.02576	11.5	21.1	35	48.980495
95	Am	Americium	5.97381	11.7	21.7	36.8	50.06895
96	Cm	Curium	5.992241	12.4	20.1	37.7	50.885292
97	Bk	Berkelium	6.19785	11.9	21.6	36	56.055455
98	Cf	Californium	6.281878	12	22.4	37.7	51.973747
99	Es	Einsteinium	6.3684	12.2	22.7	38.8	54.150658
100	Fm	Fermium	6.5	12.4	23.2	39.3	54.967
101	Md	Mendelevium	6.58	12.4	24.3	40	54.150658
102	No	Nobelium	6.62621	12.930851	25.8	41.5	60.137163
103	Lr	Lawrencium	4.96	14.544486	21.801762	43.6	56.055455
104	Rf	Rutherfordium	6.02188	14.351285	23.842616	31.872696	63.946757
105	Db	Dubnium	6.830058	13.877807	23.129678	32.925777	42.99399
106	Sg	Seaborgium	7.8	17.1	25.8	35.5	47.2
107	Bh	Bohrium	7.7	17.5	26.7	37.3	49
108	Hs	Hassium	7.6	18.2	29.3	37.7	51.2
109	Mt	Meitnerium	7.7	—	—	—	50.06895
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	—	—	—	—	—

Sources and notes

Statistics are computed for the first ionization energy; the table lists every measured step.