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Electron Configuration
Get the full and shorthand electron configuration, shells and valence electrons for any element.
Electron configuration of an element
Element: —
Configuration: —
Noble gas shorthand: —
Electrons per shell: —
Valence electrons: —
How to use the Electron Configuration
- Enter the atomic number of the element from 1 to 118.
- Press Show configuration to fill the orbitals in aufbau order.
- Read the shells, the noble gas shorthand and the valence count.
Features
- All 118 elements from hydrogen to oganesson
- Full and noble gas shorthand configurations
- Shell populations and valence electrons
- Runs locally, no uploads
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Frequently Asked Questions
Common questions about the free online electron configuration.
It lists the orbitals an atom fills in order of energy, showing how many electrons sit in
each subshell such as 1s or 2p.
The 4s orbital sits slightly lower in energy than 3d, so it fills first. That is why
potassium is written as 4s1.
The inner electrons are replaced by the previous noble gas in brackets, so sodium becomes
[Ne] 3s1 instead of the full list.
Half filled and fully filled d subshells are extra stable, so chromium is 3d5 4s1 and copper
is 3d10 4s1.
Count the electrons in the highest occupied shell. Sodium has one electron in the 3s orbital,
so it has one valence electron.
A shell is a main energy level numbered 1 to 7. Each shell holds subshells named s, p, d and
f with 2, 6, 10 and 14 electrons.
No. The configuration is worked out in your browser from the atomic number you enter, so
nothing is uploaded.
Yes. The tool is responsive and works on phones, tablets and desktops in any modern browser.
Last updated: October 10, 2026