Question

(a) Define the following terms :
(i) Valency (ii) Atomic size
(b) How do the valency and the atomic size of the elements vary while going from left to right along a period in the modern periodic table?

Answer 1

Atomic size:the size of an atom is indicated by its radius. Atomic radius is the distance between the nucleus of the atom and its outermost shell

Answer 2

valency is the nucleus of the element of its outermost sheel