Question

How does the valency of elements vary (i) in going down a group, and

(ii) in going from left to right in a period of the periodic table ?

Answer 1

Valency of elements in the same group is same from top to bottom .
Valency of elements vary from left to right as electrons are added in each element as we go from left to right due to which the attraction between the outer electrons and nucleus increases which affects the valency .