Question

Chemical reactivity of alkali metals increase while that oh halogens decrease as we move from top to bottom in a group .give reasons

Answer 1

Chemical reactivity of alkali metals is due to the donation of valence electron whereas the chemical reactivity of halogens is due to gaining of electron. On moving down from top to bottom in their respective groups, the atomic size increases due to which the electron donation ability of alkali metals increases but electron accepting ability of halogens decreases. As a result, chemical reactivity of alkali metals increase while that of halogens decrease as we move from top to bottom in a group .