Valency of Krypton (Kr)
The valency of Krypton is 0 — its outer shell is already complete, so it neither loses nor gains electrons in ordinary reactions.
Looking for Krypton's valency without wading through a whole chapter? Here is the direct answer first, then the tables and derivations examiners want to see. Every number on this page comes from the same engine that powers the interactive table. Need the whole picture instead — history, characteristics, uses, exam questions? The full Krypton page is one click away.
Counting the valence electrons
From the configuration [Ar] 3d^10 4s^2 4p^6, Krypton's outermost shell carries 8 electrons. These are the electrons shown as dots in electron-dot diagrams — the hands Krypton uses to hold other atoms.
Position check: Krypton belongs to group 18 of the periodic table, period 4.
Valency vs valence electrons
Valence electrons are what you count (8 for Krypton); valency is what the atom will do to complete its outer shell (0 here). Keep the two words straight and half the periodic-table chapter writes itself.
Students also ask
How do I find the valency of Krypton from its group?
Krypton sits in group 18; groups 13–17 follow valency = group − 10, giving 8 (though Krypton also shows 0).
Why does Krypton show a fixed valency?
Krypton has 8 valence electrons and reaches a complete outer shell in one consistent way, so its valency stays fixed at 0.