Explain the following giving an appropriate reason in each case.
(i) `O_(2)` and `F_(2)` both stabilize higher oxidation states of metals but `O_(2)` exceeds `F_(2)` in doing so.
(ii) Structure of Xenon fluorides cannot be explained by Valence Bond approach.

Answer

(i)It is due to higher lattice energy of oxides as compared to fluorides as oxide ion is dinegative whereas fluoride ion is mononegative.
(ii)It is because Xe is noble gas and has lone pair of electrons in its d-orbitals.Size of 5d orbitals in Xe is large enough for effective overlapping. 5p and 5d orbitals of Xe differ by `960kJ "mol"^(-1)`, that in `sp^(3)d` hybridisation, contribution of 5d orbital is objectionable.