Aarti Gupta
Valency or also known as combining capacity of element can be identified by looking the number of valence shell electrons.Besides this :-
1.For metals:- valency is equal to the group no. for ex. for alkali metals valency will be group no.i.e one.and for alkaline earth metals it will be two.
2. For non metals it is given by group no minus ten.for ex. boron family(13 group) valency will be
group no.(13) - 10 = 3,similarly for 14 group it will be 14 - 10 =4 and so on.