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 electrons present in element X (group 1) and element Y (group 2) are 1 and 2 respectively.
(b) The valency of the element X is one while that of the element Y is two.
(c) Metallic character decreases along a period. This means that the element X is more metallic as compared to element Y.
(d) Atomic size decreases along a period. As a result, the element Y has a smaller size than the element X.
(e) For element X : oxide `(X_(2)O),` chloride (XCI).
For element Y : oxide (YO) and chloride `(YCl_(2)).`