Electron Configuration Calculator

Enter an element symbol or atomic number to get its ground-state electron configuration, with the element’s common oxidation states.

Open in the full calculator → — with every other tool, the AI tutor and PNG export.

What it asks for

Element symbol ya atomic number

The formula

1. Aufbau principle — fill the lowest-energy orbital first.
2. Pauli exclusion principle — no two electrons in an atom may have all four quantum numbers the same, so an orbital holds at most two electrons, with opposite spins.
3. Hund's rule of maximum multiplicity — within a set of equal-energy (degenerate) orbitals, put one electron in each before pairing any, and keep those single electrons with parallel spins.

From the article Electron Configuration — Aufbau, Pauli and Hund Explained.

Worked example

Fill in order: 1s takes 2, 2s takes 2, leaving 3 electrons for 2p.

N: 1s² 2s² 2p³

Hund's rule decides how those three sit. The 2p subshell has three orbitals of equal energy (2p_x, 2p_y, 2p_z), so each gets one electron with parallel spin. Nitrogen therefore has 3 unpaired electrons, not 1. That is why it is paramagnetic and why it forms three bonds.

Worked in full in Electron Configuration — Aufbau, Pauli and Hund Explained.

Learn the method

About this tool

This is one of the tools in the Chemistry Calculator Suite, a free calculator built for IIT-JAM, CSIR-NET, GATE and CUET (Chemical Science) preparation. Nothing is behind a login and no result is stored on a server — the arithmetic runs in your own browser.

The Electron Configuration calculator above is the live tool — type your values and press its button; the answer appears in the same box. The link under it opens the full suite with this tool already selected, next to the others.

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