Which is of these nonmetals are more reactive - bromine or krypton? Explain.

The non metal which is more reactive is bromine

Explanation

Bromine is in group 17 (group of halogens) which has one unfilled spot in its valence shell.

Krypton is group 18 (groups of noble gases) which do not react with other element in normal condition due to their filled valence electron.

Therefore since bromine has unfilled valence shell it is more reactive than krypton.