What Is Valence or Valency in Chemistry Valency The combining capacity of an element is known as its valency. Formulae and valencies of common ionsElectropositive IonsMonovalentBivalentNameFormula Name FormulaPotassiumK+ BariumBa2+SodiumNa+ Calcium Ca2+Copper … [Read more...] about What Is Valence or Valency in Chemistry