Periodic table (electron configurations)

v t e Electron configurations of the chemical elements (neutral gaseous atoms in the ground state; predictions for elements 109–118)
Group:	1	2	​														3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
1s:	1 H 1																															2 He 2
[He] 2s: 2p:	3 Li 1 -	4 Be 2 -																									5 B 2 1	6 C 2 2	7 N 2 3	8 O 2 4	9 F 2 5	10 Ne 2 6
[Ne] 3s: 3p:	11 Na 1 -	12 Mg 2 -																									13 Al 2 1	14 Si 2 2	15 P 2 3	16 S 2 4	17 Cl 2 5	18 Ar 2 6
[Ar] 4s: 3d: 4p:	19 K 1 - -	20 Ca 2 - -															21 Sc 2 1 -	22 Ti 2 2 -	23 V 2 3 -	24 Cr 1 5 -	25 Mn 2 5 -	26 Fe 2 6 -	27 Co 2 7 -	28 Ni 2 8 -	29 Cu 1 10 -	30 Zn 2 10 -	31 Ga 2 10 1	32 Ge 2 10 2	33 As 2 10 3	34 Se 2 10 4	35 Br 2 10 5	36 Kr 2 10 6
[Kr] 5s: 4d: 5p:	37 Rb 1 - -	38 Sr 2 - -															39 Y 2 1 -	40 Zr 2 2 -	41 Nb 1 4 -	42 Mo 1 5 -	43 Tc 2 5 -	44 Ru 1 7 -	45 Rh 1 8 -	46 Pd - 10 -	47 Ag 1 10 -	48 Cd 2 10 -	49 In 2 10 1	50 Sn 2 10 2	51 Sb 2 10 3	52 Te 2 10 4	53 I 2 10 5	54 Xe 2 10 6
[Xe] 6s: 4f: 5d: 6p:	55 Cs 1 - - -	56 Ba 2 - - -	57 La 2 - 1 -	58 Ce 2 1 1 -	59 Pr 2 3 - -	60 Nd 2 4 - -	61 Pm 2 5 - -	62 Sm 2 6 - -	63 Eu 2 7 - -	64 Gd 2 7 1 -	65 Tb 2 9 - -	66 Dy 2 10 - -	67 Ho 2 11 - -	68 Er 2 12 - -	69 Tm 2 13 - -	70 Yb 2 14 - -	71 Lu 2 14 1 -	72 Hf 2 14 2 -	73 Ta 2 14 3 -	74 W 2 14 4 -	75 Re 2 14 5 -	76 Os 2 14 6 -	77 Ir 2 14 7 -	78 Pt 1 14 9 -	79 Au 1 14 10 -	80 Hg 2 14 10 -	81 Tl 2 14 10 1	82 Pb 2 14 10 2	83 Bi 2 14 10 3	84 Po 2 14 10 4	85 At 2 14 10 5	86 Rn 2 14 10 6
[Rn] 7s: 5f: 6d: 7p:	87 Fr 1 - - -	88 Ra 2 - - -	89 Ac 2 - 1 -	90 Th 2 - 2 -	91 Pa 2 2 1 -	92 U 2 3 1 -	93 Np 2 4 1 -	94 Pu 2 6 - -	95 Am 2 7 - -	96 Cm 2 7 1 -	97 Bk 2 9 - -	98 Cf 2 10 - -	99 Es 2 11 - -	100 Fm 2 12 - -	101 Md 2 13 - -	102 No 2 14 - -	103 Lr 2 14 - 1	104 Rf 2 14 2 -	105 Db 2 14 3 -	106 Sg 2 14 4 -	107 Bh 2 14 5 -	108 Hs 2 14 6 -	109 Mt 2 14 7 -	110 Ds 2 14 8 -	111 Rg 2 14 9 -	112 Cn 2 14 10 -	113 Nh 2 14 10 1	114 Fl 2 14 10 2	115 Mc 2 14 10 3	116 Lv 2 14 10 4	117 Ts 2 14 10 5	118 Og 2 14 10 6
s-block f-block d-block p-block

• Configurations of elements 109 and above are not available. Predictions from reliable sources have been used for these elements.
• Grayed out electron numbers indicate subshells filled to their maximum.
• Bracketed noble gas symbols on the left represent inner configurations that are the same in each period. Written out, these are:

He, 2, helium  : 1s²

Ne, 10, neon  : 1s² 2s² 2p⁶

Ar, 18, argon  : 1s² 2s² 2p⁶ 3s² 3p⁶

Kr, 36, krypton  : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

Xe, 54, xenon  : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶

Rn, 86, radon  : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶

Og, 118, oganesson  : 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d¹⁰ 7p⁶

• Note that these electron configurations are given for neutral atoms in the gas phase, which are not the same as the electron configurations for the same atoms in chemical environments. In many cases, multiple configurations are within a small range of energies and the small irregularities that arise in the d- and f-blocks are quite irrelevant chemically. ^[1] The construction of the periodic table ignores these irregularities and is based on ideal electron configurations. ^[2]
• Note the non-linear shell ordering, which comes about due to the different energies of smaller and larger shells.

References

See list of sources at Electron configurations of the elements (data page).

1. Jørgensen, Christian K. (1988). "Influence of rare earths on chemical understanding and classification". Handbook on the Physics and Chemistry of Rare Earths. Vol. 11. pp. 197–292. doi:10.1016/S0168-1273(88)11007-6. ISBN   9780444870803.
2. Jensen, William B. (2009). "Misapplying the Periodic Law" (PDF). Journal of Chemical Education. 86 (10): 1186. Bibcode:2009JChEd..86.1186J. doi: 10.1021/ed086p1186 . Retrieved 16 May 2020.