Valency of Chlorine (Cl)
The valency of Chlorine is 1 — it has 7 valence electrons, and it loses it to complete its outer shell.
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.
Counting the valence electrons
From the configuration [Ne] 3s^2 3p^5, Chlorine's outermost shell carries 7 electrons. These are the electrons shown as dots in electron-dot diagrams — the hands Chlorine uses to hold other atoms.
Position check: Chlorine belongs to group 17 of the periodic table, period 3. For main-group elements in groups 13–18, a quick rule is valency = group number − 10, which gives 7 here.
Valency vs valence electrons
Valence electrons are what you count (7 for Chlorine); valency is what the atom will do to complete its outer shell (1 here). Keep the two words straight and half the periodic-table chapter writes itself.
Students also ask
How do I find the valency of Chlorine from its group?
Chlorine sits in group 17; groups 13–17 follow valency = group − 10, giving 7 (though Chlorine also shows 1).
Why does Chlorine show a fixed valency?
Chlorine has 7 valence electrons and reaches a complete outer shell in one consistent way, so its valency stays fixed at 1.