Why are halogens most reactive ?

Explanation

The high reactivity of halogens is due to the following reasons:
(i) Low bond dissociation energies : The halogens have very low bond dissociation energies. Therefore, they can readily dissociate into atoms and react with other substances.
(ii) High electron affinity values : Halogens have very high electron affinity values and therefore have very strong tendency to gain an electron.
Thus, halogens are very reactive elements and act as strong oxidising agents.