Chlorine Electron Configuration
Chlorine (Cl) · 17 electrons · Halogen
1s2 2s2 2p6 3s2 3p5
Noble gas notation: [Ne] 3s2 3p5
Orbital diagram
↑↓
1s↑↓
2s↑↓↑↓↑↓
2p↑↓
3s↑↓↑↓↑
3p- Valence electrons
- 7
- Unpaired electrons
- 1
- Block
- p-block
- Magnetism (atom)
- paramagnetic
Electrons per shell
| K (n = 1) | 2 |
|---|---|
| L (n = 2) | 8 |
| M (n = 3) | 7 |
Chlorine ion configurations
| Ion | Electrons | Configuration |
|---|---|---|
| Cl− | 18 | [Ne] 3s2 3p6 |
How to write it
Place 17 electrons into subshells in the Aufbau order (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p), filling s with 2, p with 6, d with 10 and f with 14. Chlorine sits in period 3, group 17, in the p-block, so its last electron enters a p subshell. Replacing the inner electrons with the previous noble gas gives the shorthand [Ne] 3s2 3p5.
Try chlorine and its ions in the calculator, or see the full chlorine data sheet.
Chlorine electron configuration FAQ
What is the electron configuration of chlorine?
1s² 2s² 2p⁶ 3s² 3p⁵. Shorthand (noble gas) notation: [Ne] 3s² 3p⁵.
What is the noble gas configuration of chlorine?
[Ne] 3s² 3p⁵. The bracket stands for the Ne core electrons.
How many valence electrons does chlorine have?
7 (outer shell (n = 3)).
How many unpaired electrons does chlorine have?
1 in the ground state, following Hund’s rule. An atom with unpaired electrons is paramagnetic.
What is the electron configuration of Cl−?
[Ne] 3s² 3p⁶ (18 electrons).