Electron Configuration Calculator

Find the electron configuration for an atomic number.

Electron configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d6

Formula: fill orbitals in Aufbau order (1s, 2s, 2p, 3s, 3p, 4s, 3d …)

Step-by-step with your numbers:

1. Values used:

2. Number of electrons (Z) = 26

4. Electron configuration = 1s2 2s2 2p6 3s2 3p6 4s2 3d6

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Build an atom's ground-state electron configuration.

The math behind it

Electrons fill subshells in Aufbau (lowest-energy) order, with s holding 2, p 6, d 10 and f 14.

Iron (26): 1s2 2s2 2p6 3s2 3p6 4s2 3d6.

Exceptions?

A few elements (Cr, Cu…) deviate slightly; this uses the standard Aufbau order.