Valency of Iodine (I)
The valency of Iodine 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 Iodine. 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 Iodine page is one click away.
Counting the valence electrons
From the configuration [Kr] 4d^10 5s^2 5p^5, Iodine's outermost shell carries 7 electrons. These are the electrons shown as dots in electron-dot diagrams — the hands Iodine uses to hold other atoms.
Position check: Iodine belongs to group 17 of the periodic table, period 5. 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 Iodine); 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 Iodine from its group?
Iodine sits in group 17; groups 13–17 follow valency = group − 10, giving 7 (though Iodine also shows 1).
Why does Iodine show a fixed valency?
Iodine has 7 valence electrons and reaches a complete outer shell in one consistent way, so its valency stays fixed at 1.