Give two examples to show the anomalous behaviour of fluorine.

Explanation

Two examples which show anomalous behavious of fluorine are as follows:
(i). HF is a liquid while HCl, HBr and HI are gases. This is due to hydrogen bonding between HF molecules as F is highly electronegative atom. H-bonding is not feasible in other halogen acids.
(ii). Due to absence of d-orbitals, fluorine does not exhibit higher oxidation states i.e., `+3,+5`, and `+7` while other halogens do.