Write about the oxides and oxoanions of transition metals.

(N/A) Formation of Oxides: Transition metal oxides are formed by the reaction of metals with oxygen at high temperatures. Except for scandium,all transition metals form $MO$ type oxides,which are ionic in nature. Examples include $TiO, VO, CrO, MnO, FeO, CoO, NiO, CuO, ZnO$.
The maximum oxidation state of the metal in the oxide corresponds to the group number up to $Mn$. For example,in $Sc_2O_3, TiO_2, V_2O_5, CrO_3, Mn_2O_7$,the oxidation states are $Sc^{3+}, Ti^{4+}, V^{5+}, Cr^{6+}, Mn^{7+}$ respectively.
After group $VII (Mn)$,oxides with oxidation states higher than $+3$ are not known. $Fe_2O_3, Co_2O_3, Ni_2O_3$ are common. Oxocations: $VO_2^+$ $(V^{V})$,$VO^{2+}$ $(V^{IV})$,and $TiO^{2+}$ $(Ti^{IV})$ are stable oxocations.
Oxidation State and Properties: As the oxidation state of the metal increases,the ionic character of the oxide decreases and the covalent character increases. For example:
$(i)$ $Mn_2O_7$ is a covalent green oily oxide.
$(ii)$ $CrO_3$ and $V_2O_5$ have low melting points.
$(iii)$ Acidic Nature: Oxides with higher oxidation states are acidic. $Mn_2O_7$ and $CrO_3$ react with water to form $HMnO_4$ and $H_2CrO_4/H_2Cr_2O_7$ respectively.
$(iv)$ $V_2O_5$ is amphoteric but primarily acidic. It forms $VO_4^{3-}$ and $VO_2^+$ salts. $V_2O_5$ (amphoteric),$V_2O_4$ (less basic),and $V_2O_3$ (basic) show that as the oxidation state decreases $(V^{5+} > V^{3+} > V^{2+})$,the basic character increases.
$CrO$ is basic,while $Cr_2O_3$ is amphoteric because $Cr$ in $CrO$ is in a lower oxidation state $(+2)$ compared to $Cr$ in $Cr_2O_3$ $(+3)$.