Two elements X and Y belong to group 1 and 2 respectively in the same period of periodic table. Compare them with respect to:

(i) the number of valence electrons in their atoms;

(ii) their valences;

(iii) metallic character;

(iv) the sizes of their atoms;

(v) the formulae of their oxides;

(vi) the formulae or their chlorides.

Given: X and Y belong to same period, X belongs to group ‘1’ and Y belongs to group ‘2’.

(i) Valence electrons in any atom = Group number

So, Valence electron in element X = 1

valence electrons in Y= group number= 2.

(ii) Since valence electrons in element X= 1

So, to get stable gas electronic configuration, no. of electrons required =1

So, The valency of X = 1 whereas

The valence electrons in element Y = 2 and is already stable. So, valency of Y is 2.

(iii) Since metallic character decreases on moving from left to right in a period and X lies in group1 and Y in group 2, So, X will have more metallic character than Y.

(iv) The size of the atom decreases when move from left to right in a period. So, the size of X will be larger than Y and is 4 more than the size of Y.

(v) The Oxide of element X and Y are:

Oxide of X is X₂O

Oxide of Y is YO

(vi) Since valency of X is 1. So, Chloride of X = XCI

The valency of Y is 2, Chloride of Y = YCI₂