What information do you get from the figure about the atomic number, mass number and valency of atoms X, Y and Z ? Give your answer in a tabular form.

Explanation

In atom X, valency is equal to number of valence elctrons (2,3) =3
Atom Y has electronic configuration 2,6 valecny is eight - No of valence electrons (8-6)=2
In atom Z, valency is equal to number of valence electrons (2,8,5) or eight - no of valency (8-5) =3