Calculate electron configuration

Write an atom or ion’s occupied electron subshells from its atomic number and charge.

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ToolElectron Configuration Calculator
Input
Output
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How it works

Electrons fill the stored Aufbau sequence while respecting s², p⁶, d¹⁰, and f¹⁴ capacities. Atomic number supplies neutral count and charge adjusts it before formatting occupied subshells.

  • Neutral charge is the initial case.
  • The sequence is an educational model and does not claim every transition-metal exception.

Worked example

Iron
A d-block metal, element 26
Input
											26
Output
												Symbol: Fe
Name: Iron
Full configuration: 1s2 2s2 2p6 3s2 3p6 3d6 4s2
Noble gas shorthand: [Ar] 3d6 4s2

When to use this

Chemistry lessons write sodium’s ground state, ion exercises remove electrons, and spectroscopy references compare occupied subshells.

Edge cases

  • A positive ion has fewer electrons than its neutral atom.
  • Chromium and copper illustrate exceptions to simple filling order.
  • A negative charge adds electrons beyond the neutral configuration.

References