Electron configurations of the elements (data page)


This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. For phosphorus as an example, the concise form is 3s2 3p3. Here refers to the core electrons which are the same as for the element neon, the last noble gas before phosphorus in the periodic table. The valence electrons are written explicitly for all atoms.
Electron configurations of elements beyond hassium have never been measured; predictions are used below.
As an approximate rule, electron configurations are given by the Aufbau principle and the Madelung rule. However there are numerous exceptions; for example the lightest exception is chromium, which would be predicted to have the configuration, written as, but whose actual configuration given in the table below is.
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 irregularities shown below do not necessarily have a clear relation to chemical behaviour. For the undiscovered eighth-row elements, mixing of configurations is expected to be very important, and sometimes the result can no longer be well-described by a single configuration.

NIST

  • http://physics.nist.gov/PhysRefData/IonEnergy/ionEnergy.html ; retrieved July 2005, based on:
  • *Atomic Spectroscopy, by W.C. Martin and W.L. Wiese in Atomic, Molecular, & Optical Physics Handbook, ed. by G.W.F. Drake 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 : 5f2 6d 7s2
  • 92 U : 5f3 6d 7s2
  • 93 Np : 5f4 6d 7s2
  • 103 Lr : 5f14 7s2 7p1 question-marked
  • 104 Rf : 5f14 6d2 7s2 question-marked

CRC

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, 1996.
  • *J.E. Huheey, E.A. Keiter, and R.L. Keiter in Inorganic Chemistry : Principles of Structure and Reactivity, 4th edition, Harper Collins, New York, 1993.
  • *R.L. DeKock and H.B. Gray in Chemical Structure and bonding, Benjamin/Cummings, Menlo Park, California, 1980.
  • *A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data, Macmillan, London, UK, 1992.
  • 103 Lr : .5f14.7s2.7p1 tentative ; 2.8.18.32.32.9.2
  • 104 Rf : .5f14.6d2.7s2 tentative
  • 105 Db : .5f14.6d3.7s2 ; 2.8.18.32.32.11.2
  • 106 Sg : .5f14.6d4.7s2 ; 2.8.18.32.32.12.2
  • 107 Bh : .5f14.6d5.7s2 ; 2.8.18.32.32.13.2
  • 108 Hs : .5f14.6d6.7s2 ; 2.8.18.32.32.14.2
  • 109 Mt : .5f14.6d7.7s2 ; 2.8.18.32.32.15.2
  • 110 Ds : .5f14.6d9.7s1 ; 2.8.18.32.32.17.1
  • 111 Rg : .5f14.6d10.7s1 ; 2.8.18.32.32.18.1
  • 112 Cn : .5f14.6d10.7s2 ; 2.8.18.32.32.18.2
  • 113 Nh : .5f14.6d10.7s2.7p1 ; 2.8.18.32.32.18.3
  • 114 Fl : .5f14.6d10.7s2.7p2 ; 2.8.18.32.32.18.4
  • 115 Mc : .5f14.6d10.7s2.7p3 ; 2.8.18.32.32.18.5
  • 116 Lv : .5f14.6d10.7s2.7p4 ; 2.8.18.32.32.18.6
  • 117 Ts : .5f14.6d10.7s2.7p5 ; 2.8.18.32.32.18.7
  • 118 Og : .5f14.6d10.7s2.7p6 ; 2.8.18.32.32.18.8

Lange

  • J.A. Dean, Lange's Handbook of Chemistry, online version, McGraw-Hill, 1999; Section 4, Table 4.1 Electronic Configuration and Properties of the Elements.
  • 97 Bk : 5f8 6d 7s2
  • 103 Lr : 4f14 6d 7s2

Hill and Petrucci

  • Hill and Petrucci, General Chemistry: An Integrated Approach, Prentice Hall.
  • 58 Ce : 4f2 6s2
  • 103 Lr : 5f14 6d1 7s2

Hoffman, Lee, and Pershina

This book contains predicted electron configurations for the elements up to 172, as well as 184, based on relativistic Dirac–Fock calculations by B. Fricke in