Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.

Explanation

Upto the element Mn, the oxidation state leading to the maximum stability corresponds to value equal to sum of s-a nd d-electron i.e, the group number. For Example,
`[Sc(III)O_(2)]^(-),[Ti(IV)O_(3)]^(2-),[V(V)O_(4)]^(2-),[Mn(VII)O_(4)]^(-)`
However, for the remaining elements, the oxidation states are not related to their group numbers.