Give examples and suggest reason for the following features of the transition metals Chemistry.
(ii). A transition metal exhibits highest oxidation state in oxides and fluorides.
(iii). The highest oxidation state is exhibited in oxoanions of a metal.

Explanation

(ii) A transition metal exhibits higher oxidation states in oxides and fluorides because oxygen and fluorine are highly electronegative elements, small in size ( and strongest oxidising agents). For example , osmium shows an oxidation states of `+6` in `OsF_(6)` and vanadium shows an oxidation state of `+5` in `V_(2)O_(5)`
(iii) Oxometal anions have highest oxidation state, e.g., Cr in `Cr_(2)O_(7)^(2-)` or `CrO_(4)^(2-)` has an oxidation state of `+6` whereas Mn in `MnO_(4)^(-)` has an oxidation state of `+7` . This is again due to the combination of the metal with oxygen , which electronegative and oxidizing element.