Explain the following :
The lowest oxide of transition metal is basic whereas the highest oxide is amphoteric or acidic.

Explanation

Oxides formed in lowest oxidation states of transition metals are basic because of the ability of the metal ion to get oxidised to higher oxidation states by donating electrons. On the other hand, oxides formed in the highest oxidation state is acidic (or atleast ampoteric) because of the ability of the metal ion to get reduced to lower oxidation states by accepting electrons.
Example : `overset((II))(MnO)` is basic, while `overset((VII))(Mn_(2)O_(7))` is acidic.