Electron configurations of the elements (data page)

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Contents 1 Electron configuration 2 References 2.1 NIST 2.2 CRC 2.3 WebElements 2.4 Lange 2.5 Hill and Petrucci

Electron configuration

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.

Legend
1s	2s	2p	3s	3p	3d	4s	4p	4d	4f	5s	5p	5d	5f	6s	6p	6d	7s	7p
1 H hydrogen : 1s1
1s1
1
2 He helium : 1s2
1s2
2
3 Li lithium : 1s2 2s1
1s2	2s1
2	1
4 Be beryllium : 1s2 2s2
1s2	2s2
2	2
5 B boron : 1s2 2s2 2p1
1s2	2s2	2p1
2	3
6 C carbon : 1s2 2s2 2p2
1s2	2s2	2p2
2	4
7 N nitrogen : 1s2 2s2 2p3
1s2	2s2	2p3
2	5
8 O oxygen : 1s2 2s2 2p4
1s2	2s2	2p4
2	6
9 F fluorine : 1s2 2s2 2p5
1s2	2s2	2p5
2	7
10 Ne neon : 1s2 2s2 2p6
1s2	2s2	2p6
2	8
11 Na sodium : [Ne] 3s1
1s2	2s2	2p6	3s1
2	8		1
12 Mg magnesium : [Ne] 3s2
1s2	2s2	2p6	3s2
2	8		2
13 Al aluminium : [Ne] 3s2 3p1
1s2	2s2	2p6	3s2	3p1
2	8		3
14 Si silicon : [Ne] 3s2 3p2
1s2	2s2	2p6	3s2	3p2
2	8		4
15 P phosphorus : [Ne] 3s2 3p3
1s2	2s2	2p6	3s2	3p3
2	8		5
16 S sulfur : [Ne] 3s2 3p4
1s2	2s2	2p6	3s2	3p4
2	8		6
17 Cl chlorine : [Ne] 3s2 3p5
1s2	2s2	2p6	3s2	3p5
2	8		7
18 Ar argon : [Ne] 3s2 3p6
1s2	2s2	2p6	3s2	3p6
2	8		8
19 K potassium : [Ar] 4s1
1s2	2s2	2p6	3s2	3p6		4s1
2	8		8			1
20 Ca calcium : [Ar] 4s2
1s2	2s2	2p6	3s2	3p6		4s2
2	8		8			2
21 Sc scandium : [Ar] 3d1 4s2
1s2	2s2	2p6	3s2	3p6	3d1	4s2
2	8		9			2
22 Ti titanium : [Ar] 3d2 4s2
1s2	2s2	2p6	3s2	3p6	3d2	4s2
2	8		10			2
23 V vanadium : [Ar] 3d3 4s2
1s2	2s2	2p6	3s2	3p6	3d3	4s2
2	8		11			2
24 Cr chromium : [Ar] 3d5 4s1
1s2	2s2	2p6	3s2	3p6	3d5	4s1
2	8		13			1
25 Mn manganese : [Ar] 3d5 4s2
1s2	2s2	2p6	3s2	3p6	3d5	4s2
2	8		13			2
26 Fe iron : [Ar] 3d6 4s2
1s2	2s2	2p6	3s2	3p6	3d6	4s2
2	8		14			2
27 Co cobalt : [Ar] 3d7 4s2
1s2	2s2	2p6	3s2	3p6	3d7	4s2
2	8		15			2
28 Ni nickel : [Ar] 3d9 4s1
1s2	2s2	2p6	3s2	3p6	3d9	4s1
2	8		17			1
29 Cu copper : [Ar] 3d10 4s1
1s2	2s2	2p6	3s2	3p6	3d10	4s1
2	8		18			1
30 Zn zinc : [Ar] 3d10 4s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2
2	8		18			2
31 Ga gallium : [Ar] 3d10 4s2 4p1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p1
2	8		18			3
32 Ge germanium : [Ar] 3d10 4s2 4p2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p2
2	8		18			4
33 As arsenic : [Ar] 3d10 4s2 4p3
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p3
2	8		18			5
34 Se selenium : [Ar] 3d10 4s2 4p4
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p4
2	8		18			6
35 Br bromine : [Ar] 3d10 4s2 4p5
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p5
2	8		18			7
36 Kr krypton : [Ar] 3d10 4s2 4p6
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6
2	8		18			8
37 Rb rubidium : [Kr] 5s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6			5s1
2	8		18			8				1
38 Sr strontium : [Kr] 5s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6			5s2
2	8		18			8				2
39 Y yttrium : [Kr] 4d1 5s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d1		5s2
2	8		18			9				2
40 Zr zirconium : [Kr] 4d2 5s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d2		5s2
2	8		18			10				2
41 Nb niobium : [Kr] 4d4 5s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d4		5s1
2	8		18			12				1
42 Mo molybdenum : [Kr] 4d5 5s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d5		5s1
2	8		18			13				1
43 Tc technetium : [Kr] 4d5 5s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d5		5s2
2	8		18			13				2
44 Ru ruthenium : [Kr] 4d7 5s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d7		5s1
2	8		18			15				1
45 Rh rhodium : [Kr] 4d8 5s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d8		5s1
2	8		18			16				1
46 Pd palladium : [Kr] 4d10
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10
2	8		18			18
47 Ag silver : [Kr] 4d10 5s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s1
2	8		18			18				1
48 Cd cadmium : [Kr] 4d10 5s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2
2	8		18			18				2
49 In indium : [Kr] 4d10 5s2 5p1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p1
2	8		18			18				3
50 Sn tin : [Kr] 4d10 5s2 5p2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p2
2	8		18			18				4
51 Sb antimony : [Kr] 4d10 5s2 5p3
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p3
2	8		18			18				5
52 Te tellurium : [Kr] 4d10 5s2 5p4
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p4
53 I iodine : [Kr] 4d10 5s2 5p5
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p5
2	8		18			18				7
54 Xe xenon : [Kr] 4d10 5s2 5p6
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p6
2	8		18			18				8
55 Cs caesium : [Xe] 6s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p6			6s1
2	8		18			18				8				1
56 Ba barium : [Xe] 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p6			6s2
2	8		18			18				8				2
57 La lanthanum : [Xe] 5d1 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10		5s2	5p6	5d1		6s2
2	8		18			18				9				2
58 Ce cerium : [Xe] 4f1 5d1 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f1	5s2	5p6	5d1		6s2
2	8		18			19				9				2
59 Pr praseodymium : [Xe] 4f3 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f3	5s2	5p6			6s2
2	8		18			21				8				2
60 Nd neodymium : [Xe] 4f4 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f4	5s2	5p6			6s2
2	8		18			22				8				2
61 Pm promethium : [Xe] 4f5 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f5	5s2	5p6			6s2
2	8		18			23				8				2
62 Sm samarium : [Xe] 4f6 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f6	5s2	5p6			6s2
2	8		18			24				8				2
63 Eu europium : [Xe] 4f7 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f7	5s2	5p6			6s2
2	8		18			25				8				2
64 Gd gadolinium : [Xe] 4f7 5d1 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f7	5s2	5p6	5d1		6s2
2	8		18			25				9				2
65 Tb terbium : [Xe] 4f9 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f9	5s2	5p6			6s2
2	8		18			27				8				2
66 Dy dysprosium : [Xe] 4f10 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f10	5s2	5p6			6s2
2	8		18			28				8				2
67 Ho holmium : [Xe] 4f11 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f11	5s2	5p6			6s2
2	8		18			29				8				2
68 Er erbium : [Xe] 4f12 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f12	5s2	5p6			6s2
2	8		18			30				8				2
69 Tm thulium : [Xe] 4f13 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f13	5s2	5p6			6s2
2	8		18			31				8				2
70 Yb ytterbium : [Xe] 4f14 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6			6s2
2	8		18			32				8				2
71 Lu lutetium : [Xe] 4f14 5d1 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d1		6s2
2	8		18			32				9				2
72 Hf hafnium : [Xe] 4f14 5d2 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d2		6s2
2	8		18			32				10				2
73 Ta tantalum : [Xe] 4f14 5d3 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d3		6s2
2	8		18			32				11				2
74 W tungsten : [Xe] 4f14 5d4 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d4		6s2
2	8		18			32				12				2
75 Re rhenium : [Xe] 4f14 5d5 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d5		6s2
2	8		18			32				13				2
76 Os osmium : [Xe] 4f14 5d6 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d6		6s2
2	8		18			32				14				2
77 Ir iridium : [Xe] 4f14 5d7 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d7		6s2
2	8		18			32				15				2
78 Pt platinum : [Xe] 4f14 5d9 6s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d9		6s1
2	8		18			32				17				1
79 Au gold : [Xe] 4f14 5d10 6s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s1
2	8		18			32				18				1
80 Hg mercury : [Xe] 4f14 5d10 6s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2
2	8		18			32				18				2
81 Tl thallium : [Xe] 4f14 5d10 6s2 6p1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p1
2	8		18			32				18				3
82 Pb lead : [Xe] 4f14 5d10 6s2 6p2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p2
2	8		18			32				18				4
83 Bi bismuth : [Xe] 4f14 5d10 6s2 6p3
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p3
2	8		18			32				18				5
84 Po polonium : [Xe] 4f14 5d10 6s2 6p4
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p4
2	8		18			32				18				6
85 At astatine : [Xe] 4f14 5d10 6s2 6p5
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p5
2	8		18			32				18				7
86 Rn radon : [Xe] 4f14 5d10 6s2 6p6
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p6
2	8		18			32				18				8
87 Fr francium : [Rn] 7s1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p6		7s1
2	8		18			32				18				8			1
88 Ra radium : [Rn] 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p6		7s2
2	8		18			32				18				8			2
89 Ac actinium : [Rn] 6d1 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p6	6d1	7s2
2	8		18			32				18				9			2
90 Th thorium : [Rn] 6d2 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10		6s2	6p6	6d2	7s2
2	8		18			32				18				10			2
91 Pa protactinium : [Rn] 5f2 6d1 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f2	6s2	6p6	6d1	7s2
2	8		18			32				20				9			2
92 U uranium : [Rn] 5f3 6d1 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f3	6s2	6p6	6d1	7s2
2	8		18			32				21				9			2
93 Np neptunium : [Rn] 5f4 6d1 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f4	6s2	6p6	6d1	7s2
2	8		18			32				22				9			2
94 Pu plutonium : [Rn] 5f6 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f6	6s2	6p6		7s2
2	8		18			32				24				8			2
95 Am americium : [Rn] 5f7 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f7	6s2	6p6		7s2
2	8		18			32				25				8			2
96 Cm curium : [Rn] 5f7 6d1 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f7	6s2	6p6	6d1	7s2
2	8		18			32				25				9			2
97 Bk berkelium : [Rn] 5f9 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f9	6s2	6p6		7s2
2	8		18			32				27				8			2
98 Cf californium : [Rn] 5f10 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f10	6s2	6p6		7s2
2	8		18			32				28				8			2
99 Es einsteinium : [Rn] 5f11 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f11	6s2	6p6		7s2
2	8		18			32				29				8			2
100 Fm fermium : [Rn] 5f12 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f12	6s2	6p6		7s2
2	8		18			32				30				8			2
101 Md mendelevium : [Rn] 5f13 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f13	6s2	6p6		7s2
2	8		18			32				31				8			2
102 No nobelium : [Rn] 5f14 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6		7s2
2	8		18			32				32				8			2
103 Lr lawrencium : probably [Rn] 5f14 7s2 7p1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6		7s2	7p1
2	8		18			32				32				8			3
104 Rf rutherfordium : probably [Rn] 5f14 6d2 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d2	7s2
2	8		18			32				32				10			2
105 Db dubnium : probably [Rn] 5f14 6d3 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d3	7s2
2	8		18			32				32				11			2
106 Sg seaborgium : probably [Rn] 5f14 6d4 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d4	7s2
2	8		18			32				32				12			2
107 Bh bohrium : probably [Rn] 5f14 6d5 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d5	7s2
2	8		18			32				32				13			2
108 Hs hassium : probably [Rn] 5f14 6d6 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d6	7s2
2	8		18			32				32				14			2
109 Mt meitnerium : probably [Rn] 5f14 6d7 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d7	7s2
2	8		18			32				32				15			2
110 Ds darmstadtium : probably [Rn] 5f14 6d8 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d8	7s2
2	8		18			32				32				16			2
111 Rg roentgenium : probably [Rn] 5f14 6d9 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d9	7s2
2	8		18			32				32				17			2
112 Cn copernicium : probably [Rn] 5f14 6d10 7s2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2
2	8		18			32				32				18			2
113 Uut ununtrium : probably [Rn] 5f14 6d10 7s2 7p1
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2	7p1
2	8		18			32				32				18			3
114 Uuq ununquadium : probably [Rn] 5f14 6d10 7s2 7p2
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2	7p2
2	8		18			32				32				18			4
115 Uup ununpentium : probably [Rn] 5f14 6d10 7s2 7p3
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2	7p3
2	8		18			32				32				18			5
116 Uuh ununhexium : probably [Rn] 5f14 6d10 7s2 7p4
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2	7p4
2	8		18			32				32				18			6
117 Uus ununseptium : probably [Rn] 5f14 6d10 7s2 7p5
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2	7p5
2	8		18			32				32				18			7
118 Uuo ununoctium : probably [Rn] 5f14 6d10 7s2 7p6
1s2	2s2	2p6	3s2	3p6	3d10	4s2	4p6	4d10	4f14	5s2	5p6	5d10	5f14	6s2	6p6	6d10	7s2	7p6
2	8		18			32				32				18			8

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.

WebElements

• http://www.webelements.com/ ; retrieved July 2005, electron configurations based on:
  • Atomic, Molecular, & Optical Physics Handbook, Ed. Gordon W. F. Drake, American Institute of Physics, Woodbury, New York, USA, 1996.
  • J.E. Huheey, E.A. Keiter, and R.L. Keiter in Inorganic Chemistry : Principles of Structure and Reactivity, 4th edition, HarperCollins, New York, USA, 1993.
  • R.L. DeKock and H.B. Gray in Chemical Structure and bonding, Benjamin/Cummings, Menlo Park, California, USA, 1980.
  • A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data, Macmillan, London, UK, 1992.

• 103 Lr : [Rn].5f¹⁴.7s².7p¹ tentative ; 2.8.18.32.32.9.2 [inconsistent]
• 104 Rf : [Rn].5f¹⁴.6d².7s² tentative
• 105 Db : [Rn].5f¹⁴.6d³.7s² (a guess based upon that of tantalum) ; 2.8.18.32.32.11.2
• 106 Sg : [Rn].5f¹⁴.6d⁴.7s² (a guess based upon that of tungsten) ; 2.8.18.32.32.12.2
• 107 Bh : [Rn].5f¹⁴.6d⁵.7s² (a guess based upon that of rhenium) ; 2.8.18.32.32.13.2
• 108 Hs : [Rn].5f¹⁴.6d⁶.7s² (a guess based upon that of osmium) ; 2.8.18.32.32.14.2
• 109 Mt : [Rn].5f¹⁴.6d⁷.7s² (a guess based upon that of iridium) ; 2.8.18.32.32.15.2
• 110 Ds : [Rn].5f¹⁴.6d⁹.7s¹ (a guess based upon that of platinum) ; 2.8.18.32.32.17.1
• 111 Rg : [Rn].5f¹⁴.6d¹⁰.7s¹ (a guess based upon that of gold) ; 2.8.18.32.32.18.1
• 112 Cn : [Rn].5f¹⁴.6d¹⁰.7s² (a guess based upon that of mercury) ; 2.8.18.32.32.18.2
• 113 Uut : [Rn].5f¹⁴.6d¹⁰.7s².7p¹ (a guess based upon that of thallium) ; 2.8.18.32.32.18.3
• 114 Uuq : [Rn].5f¹⁴.6d¹⁰.7s².7p² (a guess based upon that of lead) ; 2.8.18.32.32.18.4
• 115 Uup : [Rn].5f¹⁴.6d¹⁰.7s².7p³ (a guess based upon that of bismuth) ; 2.8.18.32.32.18.5
• 116 Uuh : [Rn].5f¹⁴.6d¹⁰.7s².7p⁴ (a guess based upon that of polonium) ; 2.8.18.32.32.18.6
• 117 Uus : [Rn].5f¹⁴.6d¹⁰.7s².7p⁵ (a guess based upon that of astatine) ; 2.8.18.32.32.18.7
• 118 Uuo : [Rn].5f¹⁴.6d¹⁰.7s².7p⁶ (a guess based upon that of radon) ; 2.8.18.32.32.18.8

Lange

• J.A. Dean (ed), Lange's Handbook of Chemistry (15th Edition), online version, McGraw-Hill, 1999; Section 4, Table 4.1 Electronic Configuration and Properties of the Elements. (Elements 1–103)

• 97 Bk : [Rn] 5f⁸ 6d 7s²
• 103 Lr : [Rn] 4f¹⁴ [sic] 6d 7s²

Hill and Petrucci

• Hill and Petrucci, General Chemistry: An Integrated Approach (3rd edition), Prentice Hall. (Elements 1–106)

• 58 Ce : [Xe] 4f² 6s²
• 103 Lr : [Rn] 5f¹⁴ 6d¹ 7s²
• 104 Rf : [Rn] 5f¹⁴ 6d² 7s² (agrees with guess above)
• 105 Db : [Rn] 5f¹⁴ 6d³ 7s²
• 106 Sg : [Rn] 5f¹⁴ 6d⁴ 7s²