Other meanings are at valence In Chemistry , Valence ( which is sometimes called valency ) is the number of chemical bonds the atoms of a certain element can form . In chemistry , valence , also known as valency or valence number , is a measure of the number of bonds formed by an atom of a given element . `` Valence '' can be defined as the number of valence bonds a given atom has formed , or can form , with one or more other atoms .