All transitions metals except Sc from MO oxides which are ionic. - The highest oxidation number corresponding to the group number in transition metal oxides in attained in Sc2O3 to Mn2O7. - Acidic character increases from V2O3 to V2O4 to V2O5. - V2O4 dissolves in acids to give VO2+. - CrO is basic but Cr2O3 is amphoteric.