Electron Configuration of Helium (He)
Helium (He, Z = 2) has the electron configuration 1s^2, filling 1 shell with 2 electrons.
Teachers call it "one fact, fully handled" — exactly what this page does for Helium. The answer sits at the top in bold; scroll for the working, the shell-by-shell breakdown and the two questions students ask most. Need the whole picture instead — history, characteristics, uses, exam questions? The full Helium page is one click away.
Helium: every subshell, one by one
Start from 1s and follow the running total: this is exactly how examiners expect you to build Helium's configuration on paper.
| Subshell | Electrons | Total so far |
|---|---|---|
| 1s | 2 | 2 |
Electrons per shell (K, L, M…)
Grouped by principal quantum number instead of subshell, Helium carries 2 in shell 1. The outermost shell holds 2 electrons — the ones that do all the bonding.
How to derive it yourself
Follow the aufbau order (1s → 2s → 2p → 3s → 3p → 4s → 3d → …), pouring 2 electrons into orbitals of capacity 2 (s), 6 (p), 10 (d) and 14 (f) until none remain. Write the filled inner shells as the nearest noble-gas core — for Helium that gives 1s^2.
Students also ask
How many electron shells does Helium have?
Helium is in period 1, so its electrons occupy 1 shell, holding 2 electrons respectively.
How many valence electrons does Helium have?
Its outermost shell holds 2 electrons, so Helium has 2 valence electrons that take part in bonding.
What is the noble-gas shorthand for Helium?
Helium sits before the first noble gas, so its full configuration 1s^2 has no core to shorten.