The formulae of the oxides of two elements `X` and `Y` are `XO and Y_(2)O_(3)` respectively.
(i) Find the valencies of `X` and `Y`.
(ii) Identify the groups, in which they would be placed in the Modern Periodic Table.
(iii) Name one more element belonging to each of these groups.

Explanation

(i) Valency of element `X` is `2` while that of `Y` is `3`.
(ii) The element `X` belongs to group `2` whereas the element `Y` is present in group `13`.
(iii) The elements present in group `2` are, `Be, Mg, Ca, Sr, Ba` and `Ra`. Similarly the elements present in group `13` are, `B, Al, Ga, In and Tl`.