Electron Configuration of Chlorine (Cl)
Chlorine (Cl, Z = 17) has the electron configuration [Ne] 3s^2 3p^5, filling 3 shells with 2, 8, 7 electrons.
Teachers call it "one fact, fully handled" — exactly what this page does for Chlorine. 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 Chlorine page is one click away.
Chlorine: every subshell, one by one
Start from 1s and follow the running total: this is exactly how examiners expect you to build Chlorine's configuration on paper.
| Subshell | Electrons | Total so far |
|---|---|---|
| [Ne] | 0 | 10 |
| 3s | 2 | 12 |
| 3p | 5 | 17 |
Electrons per shell (K, L, M…)
Grouped by principal quantum number instead of subshell, Chlorine carries 2 in shell 1, 8 in shell 2, 7 in shell 3. The outermost shell holds 7 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 17 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 Chlorine that gives [Ne] 3s^2 3p^5.
Students also ask
How many electron shells does Chlorine have?
Chlorine is in period 3, so its electrons occupy 3 shells, holding 2, 8, 7 electrons respectively.
How many valence electrons does Chlorine have?
Its outermost shell holds 7 electrons, so Chlorine has 7 valence electrons that take part in bonding.
What is the noble-gas shorthand for Chlorine?
The shorthand form is exactly [Ne] 3s^2 3p^5.