Justify the inclusion of alkali metals in the same group of the periodic table with reference to the following.
(iii) Oxides and hydroxides.

Explanation

Oxidation and hydroxides: The oxides and hydroxides of all the alkali metals are strongly alkaline. Because of high electropositive character of alkali metals, their oxides and hydroxides are strongly basic.
Because of these similarities in these properties their inclusion in the same group is justifed.