Ionization energies for neutral atoms

Source: NIST

Z		element	ground shells	ground level	energy (eV)	uncertainty (eV)	references
001	H	hydrogen	1s	2S1/2	13.598434599702	0.000000000012	HDEL
002	He	helium	1s2	1S0	24.587389011000	0.000000025000	L17714
003	Li	lithium	1s22s	2S1/2	05.391714996000	0.000000022000	L12261
004	Be	beryllium	1s22s2	1S0	09.322699000000	0.000007000000	L5964
005	B	boron	1s22s22p	2P°1/2	08.298019000000	0.000003000000	L12312
006	C	carbon	1s22s22p2	3P0	11.260288000000	0.000001100000	L20057
007	N	nitrogen	1s22s22p3	4S°3/2	14.534130000000	0.000040000000	L1411
008	O	oxygen	1s22s22p4	3P2	13.618055000000	0.000007000000	L74, L3760
009	F	fluorine	1s22s22p5	2P°3/2	17.422820000000	0.000050000000	L7481, L526
010	Ne	neon	1s22s22p6	1S0	21.564541000000	0.000007000000	L8826, L1407
011	Na	sodium	[Ne]3s	2S1/2	05.139076960000	0.000000250000	L10921, L9648
012	Mg	magnesium	[Ne]3s2	1S0	07.646236000000	0.000004000000	L10635, L6969
013	Al	aluminum	[Ne]3s23p	2P°1/2	05.985769000000	0.000003000000	L7215, L10321
014	Si	silicon	[Ne]3s23p2	3P0	08.151680000000	0.000030000000	L5815
015	P	phosphorus	[Ne]3s23p3	4S°3/2	10.486686000000	0.000015000000	L5148
016	S	sulfur	[Ne]3s23p4	3P2	10.360016700000	0.000001400000	L23116
017	Cl	chlorine	[Ne]3s23p5	2P°3/2	12.967633000000	0.000016000000	L19191
018	Ar	argon	[Ne]3s23p6	1S0	15.759611900000	0.000000500000	L9217
019	K	potassium	[Ar]4s	2S1/2	04.340663730000	0.000000090000	L5451, L5783, L7185
020	Ca	calcium	[Ar]4s2	1S0	06.113154921000	0.000000000500	L22848
021	Sc	scandium	[Ar]3d4s2	2D3/2	06.561490000000	0.000060000000	L7185, L2110
022	Ti	titanium	[Ar]3d24s2	3F2	06.828120000000	0.000012000000	L17996
023	V	vanadium	[Ar]3d34s2	4F3/2	06.746187000000	0.000021000000	L17712, L20010
024	Cr	chromium	[Ar]3d54s	7S3	06.766510000000	0.000040000000	L7185, L2832
025	Mn	manganese	[Ar]3d54s2	6S5/2	07.434038000000	0.000001200000	L19057
026	Fe	iron	[Ar]3d64s2	5D4	07.902468100000	0.000001200000	L7743c109
027	Co	cobalt	[Ar]3d74s2	4F9/2	07.881010000000	0.000120000000	L10545
028	Ni	nickel	[Ar]3d84s2	3F4	07.639878000000	0.000017000000	L12369
029	Cu	copper	[Ar]3d104s	2S1/2	07.726380000000	0.000004000000	L14897
030	Zn	zinc	[Ar]3d104s2	1S0	09.394197000000	0.000006000000	L13951
031	Ga	gallium	[Ar]3d104s24p	2P°1/2	05.999302000000	0.000001200000	L5566
032	Ge	germanium	[Ar]3d104s24p2	3P0	07.899435000000	0.000012000000	L3935, L12369
033	As	arsenic	[Ar]3d104s24p3	4S°3/2	09.788550000000	0.000250000000	L1351
034	Se	selenium	[Ar]3d104s24p4	3P2	09.752368000000	0.000006000000	L21645
035	Br	bromine	[Ar]3d104s24p5	2P°3/2	11.813810000000	0.000060000000	L351, L67
036	Kr	krypton	[Ar]3d104s24p6	1S0	13.999605500000	0.000002000000	L12196
037	Rb	rubidium	[Kr]5s	2S1/2	04.177128100000	0.000001200000	L4740, L5783
038	Sr	strontium	[Kr]5s2	1S0	05.694867450000	0.000000120000	L15350, L5644
039	Y	yttrium	[Kr]4d5s2	2D3/2	06.217260000000	0.000100000000	L8844, L2111, L9735
040	Zr	zirconium	[Kr]4d25s2	3F2	06.634126000000	0.000005000000	L21107
041	Nb	niobium	[Kr]4d45s	6D1/2	06.758850000000	0.000040000000	L6829
042	Mo	molybdenum	[Kr]4d55s	7S3	07.092430000000	0.000040000000	L6829
043	Tc	technetium	[Kr]4d55s2	6S5/2	07.119380000000	0.000030000000	L15237
044	Ru	ruthenium	[Kr]4d75s	5F5	07.360500000000	0.000050000000	L10032
045	Rh	rhodium	[Kr]4d85s	4F9/2	07.458900000000	0.000050000000	L10032
046	Pd	palladium	[Kr]4d10	1S0	08.336839000000	0.000010000000	L20363
047	Ag	silver	[Kr]4d105s	2S1/2	07.576234000000	0.000025000000	L11835
048	Cd	cadmium	[Kr]4d105s2	1S0	08.993820000000	0.000016000000	L18843
049	In	indium	[Cd]5p	2P°1/2	05.786355800000	0.000000500000	L21649
050	Sn	tin	[Cd]5p2	3P0	07.343918000000	0.000012000000	L3936
051	Sb	antimony	[Cd]5p3	4S°3/2	08.608389000000	0.000012000000	L8844, L6684
052	Te	tellurium	[Cd]5p4	3P2	09.009808000000	0.000006000000	L21109
053	I	iodine	[Cd]5p5	2P°3/2	10.451236000000	0.000025000000	L13998, L22518
054	Xe	xenon	[Cd]5p6	1S0	12.129843700000	0.000001500000	L12013, L9794, L6426
055	Cs	cesium	[Xe]6s	2S1/2	03.893905727430	0.000000000170	L19479
056	Ba	barium	[Xe]6s2	1S0	05.211664600000	0.000001200000	L6347, L9224
057	La	lanthanum	[Xe]5d6s2	2D3/2	05.576900000000	0.000600000000	L3974, L16228
058	Ce	cerium	[Xe]4f5d6s2	1G°4	05.538600000000	0.000400000000	L4277
059	Pr	praseodymium	[Xe]4f36s2	4I°9/2	05.470200000000	0.000400000000	L19006
060	Nd	neodymium	[Xe]4f46s2	5I4	05.524750000000	0.000050000000	L23155
061	Pm	promethium	[Xe]4f56s2	6H°5/2	05.581870000000	0.000040000000	L20992
062	Sm	samarium	[Xe]4f66s2	7F0	05.643722000000	0.000021000000	L21624
063	Eu	europium	[Xe]4f76s2	8S°7/2	05.670385000000	0.000005000000	L13382
064	Gd	gadolinium	[Xe]4f75d6s2	9D°2	06.149800000000	0.000040000000	L11798
065	Tb	terbium	[Xe]4f96s2	6H°15/2	05.863800000000	0.000600000000	L4277
066	Dy	dysprosium	[Xe]4f106s2	5I8	05.939061000000	0.000006000000	L22122
067	Ho	holmium	[Xe]4f116s2	4I°15/2	06.021500000000	0.000600000000	L4277
068	Er	erbium	[Xe]4f126s2	3H6	06.107700000000	0.001000000000	L4277
069	Tm	thulium	[Xe]4f136s2	2F°7/2	06.184402000000	0.000009000000	L22274
070	Yb	ytterbium	[Xe]4f146s2	1S0	06.254160000000	0.000012000000	L4980
071	Lu	lutetium	[Xe]4f145d6s2	2D3/2	05.425871000000	0.000012000000	L10494, L1638
072	Hf	hafnium	[Xe]4f145d26s2	3F2	06.825070000000	0.000012000000	L14027, L10033
073	Ta	tantalum	[Xe]4f145d36s2	4F3/2	07.549571000000	0.000025000000	L13153
074	W	tungsten	[Xe]4f145d46s2	5D0	07.864030000000	0.000100000000	L11604
075	Re	rhenium	[Xe]4f145d56s2	6S5/2	07.833520000000	0.000110000000	L11604
076	Os	osmium	[Xe]4f145d66s2	5D4	08.438230000000	0.000200000000	L8105
077	Ir	iridium	[Xe]4f145d76s2	4F9/2	08.967020000000	0.000220000000	L8105
078	Pt	platinum	[Xe]4f145d96s	3D3	08.958830000000	0.000100000000	L9735, L11689
079	Au	gold	[Xe]4f145d106s	2S1/2	09.225554000000	0.000004000000	L12088
080	Hg	mercury	[Xe]4f145d106s2	1S0	10.437504000000	0.000006000000	L11931, L11984
081	Tl	thallium	[Hg]6p	2P°1/2	06.108287300000	0.000001200000	L16353
082	Pb	lead	[Hg]6p2	(1/2, 1/2)0	07.416679900000	0.000000600000	L11569
083	Bi	bismuth	[Hg]6p3	4S°3/2	07.285516000000	0.000006000000	L10664, L6247
084	Po	polonium	[Hg]6p4	3P2	08.418070000000	0.000004000000	L20887, L20886
085	At	astatine	[Hg]6p5	2P°3/2	09.317510000000	0.000080000000	L18394
086	Rn	radon	[Hg]6p6	1S0	10.748500000000		L272, L7432
087	Fr	francium	[Rn]7s	2S1/2	04.072741100000	0.000001100000	L10714
088	Ra	radium	[Rn]7s2	1S0	05.278423900000	0.000002500000	L4979
089	Ac	actinium	[Rn]6d7s2	2D3/2	05.380235000000	0.000012000000	L22136, L17893
090	Th	thorium	[Rn]6d27s2	3F2	06.306700000000	0.000250000000	L15992
091	Pa	protactinium	[Rn]5f26d7s2	4K11/2	05.890000000000	0.120000000000	L16359
092	U	uranium	[Rn]5f36d7s2	5L°6	06.194050000000	0.000060000000	L5494, L7765
093	Np	neptunium	[Rn]5f46d7s2	6L11/2	06.265608000000	0.000019000000	L23048
094	Pu	plutonium	[Rn]5f67s2	7F0	06.025760000000	0.000250000000	L15992, L11260
095	Am	americium	[Rn]5f77s2	8S°7/2	05.973810000000	0.000250000000	L15992
096	Cm	curium	[Rn]5f76d7s2	9D°2	05.992241000000	0.000020000000	L22423
097	Bk	berkelium	[Rn]5f97s2	6H°15/2	06.197850000000	0.000250000000	L15992
098	Cf	californium	[Rn]5f107s2	5I8	06.281878000000	0.000006000000	L22260
099	Es	einsteinium	[Rn]5f117s2	4I°15/2	06.368400000000	0.000060000000	L22449
100	Fm	fermium	[Rn]5f127s2	3H6	06.500000000000	0.070000000000	L16359
101	Md	mendelevium	[Rn]5f137s2	2F°7/2	06.580000000000	0.070000000000	L16359
102	No	nobelium	[Rn]5f147s2	1S0	06.626210000000	0.000050000000	L20870
103	Lr	lawrencium	[Rn]5f147s27p	2P°1/2	04.960000000000	0.050000000000	L21372
104	Rf	rutherfordium	[Rn]5f146d27s2	3F2	06.020000000000	0.040000000000	L19691
105	Db	dubnium	[Rn]5f146d37s2	4F3/2	06.800000000000	0.500000000000	L12825
106	Sg	seaborgium	[Rn]5f146d47s2	0	07.800000000000	0.500000000000	L7830
107	Bh	bohrium	[Rn]5f146d57s2	5/2	07.700000000000	0.500000000000	L13544
108	Hs	hassium	[Rn]5f146d67s2	4	07.600000000000	0.500000000000	L13544
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			?