Full configuration
1s² 2s² 2p⁶ 3s² 3p⁶
In the short form, [Ne] stands for the 10 electrons of neon, the noble gas before argon. Only the electrons after it are written out.
Orbital diagram
2p↑↓↑↓↑↓
3s↑↓
3p↑↓↑↓↑↓
Outer subshells only. Each box is an orbital; electrons fill singly first (Hund's rule), then pair up with opposite spins.
What the configuration tells you
Argon is in group 18, period 3, in the p-block. It has a full outer shell, which is why it's so unreactive.
Nearby elements
| Z | Element | Configuration |
|---|---|---|
| 15 | Phosphorus | [Ne] 3s² 3p³ |
| 16 | Sulphur | [Ne] 3s² 3p⁴ |
| 17 | Chlorine | [Ne] 3s² 3p⁵ |
| 19 | Potassium | [Ar] 4s¹ |
| 20 | Calcium | [Ar] 4s² |
| 21 | Scandium | [Ar] 3d¹ 4s² |
Questions students ask
What is the electronic configuration of argon?
[Ne] 3s² 3p⁶, or in full, 1s² 2s² 2p⁶ 3s² 3p⁶. Argon has atomic number 18.
How many electrons are in each shell of argon?
2, 8, 8 (K, L, M, N… shells in order).
How many unpaired electrons does argon have?
0 in the ground state, so argon atoms are diamagnetic.