How many of the following are square planar?

(a) $\begin{array}{l}\mathrm{Ni}(\mathrm{dmg}{)}_2\end{array}$      (b) ${\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{2-}$

(c) ${\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{4-}$  (d) $\left[\mathrm{Ni}(\mathrm{CO}{)}_4\right]$

(e) ${\left[\mathrm{Ni}(\mathrm{Cl}{)}_4\right]}^{2-}$    (f) ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$

(g) ${\mathrm{K}}_2{\mathrm{CrO}}_4$           (h) ${\mathrm{KMnO}}_4$      

(i) ${\mathrm{K}}_2{\mathrm{MnO}}_4$          (j) ${\mathrm{CrO}}_2{\mathrm{Cl}}_2$

Square planar is a molecular shape that results when there are four bonds and two lone pairs on the central atom in the molecule. Here, the molecule which has the square planer shape are,

(a) $\begin{array}{l}\mathrm{Ni}(\mathrm{dmg}{)}_2\end{array}$ (b) ${\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{2-}$are square planar.

Hence, correct answer is 0002