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Atomic Reference Data for Electronic Structure Calculations, Electronic Configurations of the Elements

The ground electronic configurations of the neutral elements used here are obtained from the most recent compilation [1] produced by the NIST Atomic Physics Division. Some of these differ from those found in older references. The ground electronic configurations of first cations are in most cases obtained from a previous compilation [2]. There are several cases for which that work gives no identification of configuration, and for these we have used identifications made in the scientific literature. The cases concerned are: Ta+ [3], W+ [4], Re+ [5], Os+ [6], Ir+ [7], Po+ [8], At+ [9], Rn+ [10], Fr+ [11], Pa+ [12], and U+ [12].

The ground electronic configurations of the elements H through U and their first cations are given below. The notation [X] indicates that all subshells associated with the noble gas X are fully occupied.

ZSymbolNeutralPositive ion
1H1s1-
2He1s21s1
3Li[He] 2s11s2
4Be[He] 2s2[He] 2s1
5B[He] 2s2 2p1[He] 2s2
6C[He] 2s2 2p2[He] 2s2 2p1
7N[He] 2s2 2p3[He] 2s2 2p2
8O[He] 2s2 2p4[He] 2s2 2p3
9F[He] 2s2 2p5[He] 2s2 2p4
10Ne[He] 2s2 2p6[He] 2s2 2p5
11Na[Ne] 3s1[He] 2s2 2p6
12Mg[Ne] 3s2[Ne] 3s1
13Al[Ne] 3s2 3p1[Ne] 3s2
14Si[Ne] 3s2 3p2[Ne] 3s2 3p1
15P[Ne] 3s2 3p3[Ne] 3s2 3p2
16S[Ne]3s2 3p4[Ne] 3s2 3p3
17Cl[Ne] 3s2 3p5[Ne] 3s2 3p4
18Ar[Ne] 3s2 3p6[Ne] 3s2 3p5
19K[Ar] 4s1[Ne] 3s2 3p6
20Ca[Ar] 4s2[Ar] 4s1
21Sc[Ar] 3d1 4s2[Ar] 3d1 4s1
22Ti[Ar] 3d2 4s2[Ar] 3d2 4s1
23V[Ar] 3d3 4s2[Ar] 3d4
24Cr[Ar] 3d5 4s1[Ar] 3d5
25Mn[Ar] 3d5 4s2[Ar] 3d5 4s1
26Fe[Ar] 3d6 4s2[Ar] 3d6 4s1
27Co[Ar] 3d7 4s2[Ar] 3d8
28Ni[Ar] 3d8 4s2[Ar] 3d9
29Cu[Ar] 3d10 4s1[Ar] 3d10
30Zn[Ar] 3d10 4s2[Ar] 3d10 4s1
31Ga[Ar] 3d10 4s2 4p1[Ar] 3d10 4s2
32Ge[Ar] 3d10 4s2 4p2[Ar] 3d10 4s2 4p1
33As[Ar] 3d10 4s2 4p3[Ar] 3d10 4s2 4p2
34Se[Ar] 3d10 4s2 4p4[Ar] 3d10 4s2 4p3
35Br[Ar] 3d10 4s2 4p5[Ar] 3d10 4s2 4p4
36Kr[Ar] 3d10 4s2 4p6[Ar] 3d10 4s2 4p5
37Rb[Kr] 5s1[Ar] 3d10 4s2 4p6
38Sr[Kr] 5s2[Kr] 5s1
39Y[Kr] 4d1 5s2[Kr] 5s2
40Zr[Kr] 4d2 5s2[Kr] 4d2 5s1
41Nb[Kr] 4d4 5s1[Kr] 4d4
42Mo[Kr] 4d5 5s1[Kr] 4d5
43Tc[Kr] 4d5 5s2[Kr] 4d5 5s1
44Ru[Kr] 4d7 5s1[Kr] 4d7
45Rh[Kr] 4d8 5s1[Kr] 4d8
46Pd[Kr] 4d10[Kr] 4d9
47Ag[Kr] 4d10 5s1[Kr] 4d10
48Cd[Kr] 4d10 5s2[Kr] 4d10 5s1
49In[Kr] 4d10 5s2 5p1[Kr] 4d10 5s2
50Sn[Kr] 4d10 5s2 5p2[Kr] 4d10 5s2 5p1
51Sb[Kr] 4d10 5s2 5p3[Kr] 4d10 5s2 5p2
52Te[Kr] 4d10 5s2 5p4[Kr] 4d10 5s2 5p3
53I[Kr] 4d10 5s2 5p5[Kr] 4d10 5s2 5p4
54Xe[Kr] 4d10 5s2 5p6[Kr] 4d10 5s2 5p5
55Cs[Xe] 6s1[Kr] 4d10 5s2 5p6
56Ba[Xe] 6s2[Xe] 6s1
57La[Xe] 5d1 6s2[Xe] 5d2
58Ce[Xe] 4f1 5d1 6s2[Xe] 4f1 5d2
59Pr[Xe] 4f3 6s2[Xe] 4f3 6s1
60Nd[Xe] 4f4 6s2[Xe] 4f4 6s1
61Pm[Xe] 4f5 6s2[Xe] 4f5 6s1
62Sm[Xe] 4f6 6s2[Xe] 4f6 6s1
63Eu[Xe] 4f7 6s2[Xe] 4f7 6s1
64Gd[Xe] 4f7 5d1 6s2[Xe] 4f7 5d1 6s1
65Tb[Xe] 4f9 6s2[Xe] 4f9 6s1
66Dy[Xe] 4f10 6s2[Xe] 4f10 6s1
67Ho[Xe] 4f11 6s2[Xe] 4f11 6s1
68Er[Xe] 4f12 6s2[Xe] 4f12 6s1
69Tm[Xe] 4f13 6s2[Xe] 4f13 6s1
70Yb[Xe] 4f14 6s2[Xe] 4f14 6s1
71Lu[Xe] 4f14 5d1 6s2[Xe] 4f14 6s2
72Hf[Xe] 4f14 5d2 6s2[Xe] 4f14 5d1 6s2
73Ta[Xe] 4f14 5d3 6s2[Xe] 4f14 5d3 6s1
74W[Xe] 4f14 5d4 6s2[Xe] 4f14 5d4 6s1
75Re[Xe] 4f14 5d5 6s2[Xe] 4f14 5d5 6s1
76Os[Xe] 4f14 5d6 6s2[Xe] 4f14 5d6 6s1
77Ir[Xe] 4f14 5d7 6s2[Xe] 4f14 5d7 6s1
78Pt[Xe] 4f14 5d9 6s1[Xe] 4f14 5d9
79Au[Xe] 4f14 5d10 6s1[Xe] 4f14 5d10
80Hg[Xe] 4f14 5d10 6s2[Xe] 4f14 5d10 6s1
81Tl[Xe] 4f14 5d10 6s2 6p1[Xe] 4f14 5d10 6s2
82Pb[Xe] 4f14 5d10 6s2 6p2[Xe] 4f14 5d10 6s2 6p1
83Bi[Xe] 4f14 5d10 6s2 6p3[Xe] 4f14 5d10 6s2 6p2
84Po[Xe] 4f14 5d10 6s2 6p4[Xe] 4f14 5d10 6s2 6p3
85At[Xe] 4f14 5d10 6s2 6p5[Xe] 4f14 5d10 6s2 6p4
86Rn[Xe] 4f14 5d10 6s2 6p6[Xe] 4f14 5d10 6s2 6p5
87Fr[Rn] 7s1[Xe] 4f14 5d10 6s2 6p6
88Ra[Rn] 7s2[Rn] 7s1
89Ac[Rn] 6d1 7s2[Rn] 7s2
90Th[Rn] 6d2 7s2[Rn] 6d2 7s1
91Pa[Rn] 5f2 6d1 7s2[Rn] 5f2 7s2
92U[Rn] 5f3 6d1 7s2[Rn] 5f3 7s2

Sources:
  1. W.C. Martin and W.L. Wiese, "Atomic Spectroscopy," in Atomic, Molecular, and Optical Physics Handbook, ed. G.W.F. Drake, American Institute of Physics (Woodbury NY 1996).
  2. C.E. Moore, Ionization Potentials and Ionization Limits Derived from the Analyses of Optical Spectra, Natl. Stand. Ref. Data Ser., Natl. Bur. Stand.(U.S.), 34 (1970).
  3. J. Wyart, Opt. Pura Apl. (Spain) 10, 177 (1977); C. Kiess, J. Res. Nat. Bur. Standards 66A, 111 (1962).
  4. D.D. Lann, J. Res. Nat. Bur. Standards 68A, 207 (1964).
  5. W.F. Meggers, J. Res. Nat. Bur. Standards 61, 441 (1958).
  6. Th. A.M. van Kleef and P.F.A. Klinkenberg, Physica 27, 83 (1961).
  7. Th. A.M. van Kleef and B.C. Matsh, Physica 95C, 251 (1978).
  8. G.W. Charles, J. Opt. Soc. Am. 56, 1292 (1966).
  9. Estimate of present authors.
  10. C. Moore Atomic Energy Levels, NBS 35 3 (1971).
  11. Estimate of present authors.
  12. J. Blaise and J.-F. Wyart Energy levels and atomic spectra of actinides, International Tables of Selected Constants 20, Tables de Constantes (Paris, France 1992).
Created October 15, 2015, Updated April 24, 2017