(1)V2+<Cr2+<Mn2+<Fe2+:paramagneticbehaviour(2)Ni2+<Co2+<Fe2+<Mn2+:ionicsize(3)Co3+<Fe3+<Cr3+<SC3+:stabilityinaqueoussolution(4)Sc<Ti<Cr<Mn:numberofoxidationstates