A1: Atomic Electron Configurations

Electron configurations of the neutral gaseous atoms in the ground state. Given by subshells in concise form, by subshells written out, and by number of electrons per shell.

1 H hydrogen : 1s^1
1s^1
1
2 He helium : 1s^2
1s^2
2
3 Li lithium : 1s^2 2s^1
1s^2	2s^1
2	1
4 Be beryllium : 1s^2 2s^2
1s^2	2s^2
2	2
5 B boron : 1s^2 2s^2 2p^1
1s^2	2s^2	2p^1
2	3
6 C carbon : 1s^2 2s^2 2p^2
1s^2	2s^2	2p^2
2	4
7 N nitrogen : 1s^2 2s^2 2p^3
1s^2	2s^2	2p^3
2	5
8 O oxygen : 1s^2 2s^2 2p^4
1s^2	2s^2	2p^4
2	6
9 F fluorine : 1s^2 2s^2 2p^5
1s^2	2s^2	2p^5
2	7
10 Ne neon : 1s^2 2s^2 2p^6
1s^2	2s^2	2p^6
2	8
11 Na sodium : [Ne] 3s^1
1s^2	2s^2	2p^6	3s^1
2	8		1
12 Mg magnesium : [Ne] 3s^2
1s^2	2s^2	2p^6	3s^2
2	8		2
13 Al aluminium : [Ne] 3s^2 3p^1
1s^2	2s^2	2p^6	3s^2	3p^1
2	8		3
14 Si silicon : [Ne] 3s^2 3p^2
1s^2	2s^2	2p^6	3s^2	3p^2
2	8		4
15 P phosphorus : [Ne] 3s^2 3p^3
1s^2	2s^2	2p^6	3s^2	3p^3
2	8		5
16 S sulfur : [Ne] 3s^2 3p^4
1s^2	2s^2	2p^6	3s^2	3p^4
2	8		6
17 Cl chlorine : [Ne] 3s^2 3p^5
1s^2	2s^2	2p^6	3s^2	3p^5
2	8		7
18 Ar argon : [Ne] 3s^2 3p^6
1s^2	2s^2	2p^6	3s^2	3p^6
2	8		8
19 K potassium : [Ar] 4s^1
1s^2	2s^2	2p^6	3s^2	3p^6		4s^1
2	8		8			1
20 Ca calcium : [Ar] 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6		4s^2
2	8		8			2
21 Sc scandium : [Ar] 3d^1 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^1	4s^2
2	8		9			2
22 Ti titanium : [Ar] 3d^2 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^2	4s^2
2	8		10			2
23 V vanadium : [Ar] 3d^3 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^3	4s^2
2	8		11			2
24 Cr chromium : [Ar] 3d^5 4s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^5	4s^1
2	8		13			1
25 Mn manganese : [Ar] 3d^5 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^5	4s^2
2	8		13			2
26 Fe iron : [Ar] 3d^6 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^6	4s^2
2	8		14			2
27 Co cobalt : [Ar] 3d^7 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^7	4s^2
2	8		15			2
28 Ni nickel : [Ar] 3d^8 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^8	4s^2
2	8		16			2
29 Cu copper : [Ar] 3d^10 4s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^1
2	8		18			1
30 Zn zinc : [Ar] 3d^10 4s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2
2	8		18			2
31 Ga gallium : [Ar] 3d^10 4s^2 4p^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^1
2	8		18			3
32 Ge germanium : [Ar] 3d^10 4s^2 4p^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^2
2	8		18			4
33 As arsenic : [Ar] 3d^10 4s^2 4p^3
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^3
2	8		18			5
34 Se selenium : [Ar] 3d^10 4s^2 4p^4
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^4
2	8		18			6
35 Br bromine : [Ar] 3d^10 4s^2 4p^5
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^5
2	8		18			7
36 Kr krypton : [Ar] 3d^10 4s^2 4p^6
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6
2	8		18			8
37 Rb rubidium : [Kr] 5s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6			5s^1
2	8		18			8				1
38 Sr strontium : [Kr] 5s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6			5s^2
2	8		18			8				2
39 Y yttrium : [Kr] 4d^1 5s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^1		5s^2
2	8		18			9				2
40 Zr zirconium : [Kr] 4d^2 5s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^2		5s^2
2	8		18			10				2
41 Nb niobium : [Kr] 4d^4 5s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^4		5s^1
2	8		18			12				1
42 Mo molybdenum : [Kr] 4d^5 5s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^5		5s^1
2	8		18			13				1
43 Tc technetium : [Kr] 4d^5 5s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^5		5s^2
2	8		18			13				2
44 Ru ruthenium : [Kr] 4d^7 5s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^7		5s^1
2	8		18			15				1
45 Rh rhodium : [Kr] 4d^8 5s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^8		5s^1
2	8		18			16				1
46 Pd palladium : [Kr] 4d^10
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10
2	8		18			18
47 Ag silver : [Kr] 4d^10 5s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^1
2	8		18			18				1
48 Cd cadmium : [Kr] 4d^10 5s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2
2	8		18			18				2
49 In indium : [Kr] 4d^10 5s^2 5p^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^1
2	8		18			18				3
50 Sn tin : [Kr] 4d^10 5s^2 5p^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^2
2	8		18			18				4
51 Sb antimony : [Kr] 4d^10 5s^2 5p^3
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^3
2	8		18			18				5
52 Te tellurium : [Kr] 4d^10 5s^2 5p^4
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^4
2	8		18			18				6
53 I iodine : [Kr] 4d^10 5s^2 5p^5
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^5
2	8		18			18				7
54 Xe xenon : [Kr] 4d^10 5s^2 5p^6
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^6
2	8		18			18				8
55 Cs caesium : [Xe] 6s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^6			6s^1
2	8		18			18				8				1
56 Ba barium : [Xe] 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^6			6s^2
2	8		18			18				8				2
57 La lanthanum : [Xe] 5d^1 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10		5s^2	5p^6	5d^1		6s^2
2	8		18			18				9				2
58 Ce cerium : [Xe] 4f^1 5d^1 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^1	5s^2	5p^6	5d^1		6s^2
2	8		18			19				9				2
59 Pr praseodymium : [Xe] 4f^3 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^3	5s^2	5p^6			6s^2
2	8		18			21				8				2
60 Nd neodymium : [Xe] 4f^4 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^4	5s^2	5p^6			6s^2
2	8		18			22				8				2
61 Pm promethium : [Xe] 4f^5 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^5	5s^2	5p^6			6s^2
2	8		18			23				8				2
62 Sm samarium : [Xe] 4f^6 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^6	5s^2	5p^6			6s^2
2	8		18			24				8				2
63 Eu europium : [Xe] 4f^7 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^7	5s^2	5p^6			6s^2
2	8		18			25				8				2
64 Gd gadolinium : [Xe] 4f^7 5d^1 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^7	5s^2	5p^6	5d^1		6s^2
2	8		18			25				9				2
65 Tb terbium : [Xe] 4f^9 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^9	5s^2	5p^6			6s^2
2	8		18			27				8				2
66 Dy dysprosium : [Xe] 4f^10 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^10	5s^2	5p^6			6s^2
2	8		18			28				8				2
67 Ho holmium : [Xe] 4f^11 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^11	5s^2	5p^6			6s^2
2	8		18			29				8				2
68 Er erbium : [Xe] 4f^12 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^12	5s^2	5p^6			6s^2
2	8		18			30				8				2
69 Tm thulium : [Xe] 4f^13 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^13	5s^2	5p^6			6s^2
2	8		18			31				8				2
70 Yb ytterbium : [Xe] 4f^14 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6			6s^2
2	8		18			32				8				2
71 Lu lutetium : [Xe] 4f^14 5d^1 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^1		6s^2
2	8		18			32				9				2
72 Hf hafnium : [Xe] 4f^14 5d^2 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^2		6s^2
2	8		18			32				10				2
73 Ta tantalum : [Xe] 4f^14 5d^3 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^3		6s^2
2	8		18			32				11				2
74 W tungsten : [Xe] 4f^14 5d^4 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^4		6s^2
2	8		18			32				12				2
75 Re rhenium : [Xe] 4f^14 5d^5 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^5		6s^2
2	8		18			32				13				2
76 Os osmium : [Xe] 4f^14 5d^6 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^6		6s^2
2	8		18			32				14				2
77 Ir iridium : [Xe] 4f^14 5d^7 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^7		6s^2
2	8		18			32				15				2
78 Pt platinum : [Xe] 4f^14 5d^9 6s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^9		6s^1
2	8		18			32				17				1
79 Au gold : [Xe] 4f^14 5d^10 6s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^1
2	8		18			32				18				1
80 Hg mercury : [Xe] 4f^14 5d^10 6s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2
2	8		18			32				18				2
81 Tl thallium : [Xe] 4f^14 5d^10 6s^2 6p^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^1
2	8		18			32				18				3
82 Pb lead : [Xe] 4f^14 5d^10 6s^2 6p^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^2
2	8		18			32				18				4
83 Bi bismuth : [Xe] 4f^14 5d^10 6s^2 6p^3
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^3
2	8		18			32				18				5
84 Po polonium : [Xe] 4f^14 5d^10 6s^2 6p^4
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^4
2	8		18			32				18				6
85 At astatine : [Xe] 4f^14 5d^10 6s^2 6p^5
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^5
2	8		18			32				18				7
86 Rn radon : [Xe] 4f^14 5d^10 6s^2 6p^6
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^6
2	8		18			32				18				8
87 Fr francium : [Rn] 7s^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^6		7s^1
2	8		18			32				18				8			1
88 Ra radium : [Rn] 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^6		7s^2
2	8		18			32				18				8			2
89 Ac actinium : [Rn] 6d^1 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^6	6d^1	7s^2
2	8		18			32				18				9			2
90 Th thorium : [Rn] 6d^2 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10		6s^2	6p^6	6d^2	7s^2
2	8		18			32				18				10			2
91 Pa protactinium : [Rn] 5f^2 6d^1 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^2	6s^2	6p^6	6d^1	7s^2
2	8		18			32				20				9			2
92 U uranium : [Rn] 5f^3 6d^1 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^3	6s^2	6p^6	6d^1	7s^2
2	8		18			32				21				9			2
93 Np neptunium : [Rn] 5f^4 6d^1 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^4	6s^2	6p^6	6d^1	7s^2
2	8		18			32				22				9			2
94 Pu plutonium : [Rn] 5f^6 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^6	6s^2	6p^6		7s^2
2	8		18			32				24				8			2
95 Am americium : [Rn] 5f^7 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^7	6s^2	6p^6		7s^2
2	8		18			32				25				8			2
96 Cm curium : [Rn] 5f^7 6d^1 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^7	6s^2	6p^6	6d^1	7s^2
2	8		18			32				25				9			2
97 Bk berkelium : [Rn] 5f^9 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^9	6s^2	6p^6		7s^2
2	8		18			32				27				8			2
98 Cf californium : [Rn] 5f^10 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^10	6s^2	6p^6		7s^2
2	8		18			32				28				8			2
99 Es einsteinium : [Rn] 5f^11 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^11	6s^2	6p^6		7s^2
2	8		18			32				29				8			2
100 Fm fermium : [Rn] 5f^12 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^12	6s^2	6p^6		7s^2
2	8		18			32				30				8			2
101 Md mendelevium : [Rn] 5f^13 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^13	6s^2	6p^6		7s^2
2	8		18			32				31				8			2
102 No nobelium : [Rn] 5f^14 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^14	6s^2	6p^6		7s^2
2	8		18			32				32				8			2
103 Lr lawrencium : probably [Rn] 5f^14 7s^2 7p^1
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^14	6s^2	6p^6		7s^2	7p^1
2	8		18			32				32				8			3
104 Rf rutherfordium : probably [Rn] 5f^14 6d^2 7s^2
1s^2	2s^2	2p^6	3s^2	3p^6	3d^10	4s^2	4p^6	4d^10	4f^14	5s^2	5p^6	5d^10	5f^14	6s^2	6p^6	6d^2	7s^2
2	8		18			32				32				10			2

References

All sources concur with the data above except in the separately listed instances:

NIST

• http://physics.nist.gov/PhysRefData/IonEnergy/ionEnergy.html ; retrieved July 2005, (elements 1–104) based on:
  • Atomic Spectroscopy, by W.C. Martin and W.L. Wiese in Atomic, Molecular, & Optical Physics Handbook, ed. by G.W.F. Drake (AIP, Woodbury, NY, 1996) Chapter 10, pp. 135–153.

This website is also cited in the CRC Handbook as source of Section 1, subsection Electron Configuration of Neutral Atoms in the Ground State.

• 91 Pa : [Rn] 5f²(³H₄) 6d 7s²
• 92 U : [Rn] 5f³(⁴I^o_9/2) 6d 7s²
• 93 Np : [Rn] 5f⁴(⁵I₄) 6d 7s²
• 103 Lr : [Rn] 5f¹⁴ 7s² 7p¹ question-marked
• 104 Rf : [Rn] 5f¹⁴ 6d² 7s² question-marked

CRC

• David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition, online version. CRC Press. Boca Raton, Florida, 2003; Section 1, Basic Constants, Units, and Conversion Factors; Electron Configuration of Neutral Atoms in the Ground State. (elements 1–104)
• Also subsection Periodic Table of the Elements, (elements 1–103) based on:
  • G. J. Leigh, Editor, Nomenclature of Inorganic Chemistry, Blackwell Scientific Publications, Oxford, 1990.
  • Chemical and Engineering News, 63(5), 27, 1985.
  • Atomic Weights of the Elements, 1999, Pure & Appl. Chem., 73, 667, 2001.

References

• en.Wikipedia.org/wiki/Electro...28data_page%29

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