Chemistry reference calculator
Electron Configuration Calculator
Look up the reviewed ground-state electron configuration of a neutral element from atomic number 1 through 118.
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Choose an element
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Result
Formula and method
Local orbital filling with explicit exceptions is checked against NIST Atomic Spectra Database 5.12 (elements 1–108) and the Royal Society of Chemistry periodic table (109–118). Superheavy configurations include theoretical predictions and can vary by reference. Reviewed October 7, 2026.
Worked example
Iron (Z = 26) has the shorthand [Ar] 3d6 4s2 and shell distribution 2, 8, 14, 2.
Limitations
Neutral ground-state atoms only. Ions, excited states, term symbols, bonding, and chemical behavior are outside scope.