Valency of Bismuth (Bi)
Bismuth shows variable valency — most commonly 3 and 5 — because it is a p-block element whose outer electrons can join bonding in more than one way.
Teachers call it "one fact, fully handled" — exactly what this page does for Bismuth. 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 Bismuth page is one click away.
Counting the valence electrons
From the configuration [Xe] 4f^14 5d^10 6s^2 6p^3, Bismuth's outermost shell carries 5 electrons. These are the electrons shown as dots in electron-dot diagrams — the hands Bismuth uses to hold other atoms.
Position check: Bismuth belongs to group 15 of the periodic table, period 6. For main-group elements in groups 13–18, a quick rule is valency = group number − 10, which gives 5 here.
Why Bismuth has more than one valency
The common valencies are 3 and 5. Both the outer s electrons and the nearby (n−1)d electrons sit close in energy, so Bismuth can offer different numbers of them in different compounds — giving ions such as Bi³⁺ and Bi⁵⁺ and families of compounds like Bi₃X₂ / Bi₅X₂.
Valency vs valence electrons
Valence electrons are what you count (5 for Bismuth); valency is what the atom will do to complete its outer shell (3 and 5 here). Keep the two words straight and half the periodic-table chapter writes itself.
Students also ask
How do I find the valency of Bismuth from its group?
Bismuth sits in group 15; groups 13–17 follow valency = group − 10, giving 5 (though Bismuth also shows 3 and 5).
Why does Bismuth show variable valency?
Because both its outer shell and the nearby inner subshell can participate in bonding, Bismuth forms more than one stable ion — hence valencies 3 and 5.