How would you account for the following:
(i) The electron gain enthalpy with negative sign is less for oxygen than that for sulphur.
(ii) Phosphorus shows greater tendency for catenation than nitrogen.
(iii) Fluorine never acts as the central atom in polyatomic interhalogen compounds.
(i) The least negative electron gain enthalpy of oxygen is due to small size and more interelectronic repulsion with coming electron.
(ii) The bond strength of P-P is more than N-N, therefore phosphorus shows more tendency for catenation than nitrogen.
(iii) Because F being smaller, it cannot accomodate larger sized other halogen atoms around it. Due to the absence of d-orbitals, F does not show positive oxidation state of +3, +5, +7 needed for the formation of polyatomic interhalogen compounds.