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Chemistry LibreTexts

A1: Atomic Electron Configurations

  • Page ID
    2180
  • 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 : 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] 3d8 4s2
    1s2 2s2 2p6 3s2 3p6 3d8 4s2
    2 8 16 2
    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
    2 8 18 18 6
    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

    References

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

    NIST

    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(4Io9/2) 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.