Question

Two elements $X$ and $Y$ belong to group 1 and 2 respectively in the same period. Compare them with respect to:
a) the number of valence electrons
b) valency
c) metallic character
d) size of the atoms
e) formulae of their oxides and chlorides

Answer 1

a) The valence number of electrons in X is 1 and in Y is 2.

b) The valency of the element is determined by the number of electrons in the outermost shell . Thus, the valency of element X is 1 and Y is 2.

c) Element X is more metallic than Y.

d) The size of element X is more than Y.

e) The formulae of oxide of element X is $X_{2}O$ and Y is YO

The formulae of chlorides of element X is XCl and Y is $YC{l}_2$