$\begin{array}{1 1} (1)
V^{2+} < Cr^{2+} < Mn^{2+} < Fe^{2+} : \;paramagnetic \;behaviour \\
(2) Ni^{2+} < Co^{2+} < Fe^{2+} < Mn^{2+} \; : ionic\; size \\ (3) Co^{3+} < Fe^{3+} < Cr^{3+} < SC^{3+} \; :stability\; in \;aqueous\; solution \\ (4) Sc < Ti < Cr < Mn : number\; of\; oxidation\; states \end {array}$