question_answer

Nickel \[\left( Z = 28 \right)\] combines with a uninegative monodentate ligand \[{{X}^{-}}\] to form a paramagnetic complex\[{{[Ni{{X}_{4}}]}^{2-}}\]. The number of unpaired electron(s) in the nickel and geometry of this complex ion are, respectively

A) one, square planar         

B) two, square planar

C) one, tetrahedral

D) two, tetrahedral

Correct Answer: D

Solution :

\[{{\left[ Ni {{X}_{4}} \right]}^{2-}}\], the electronic configuration of \[N{{i}^{2+}}\] is   It contains two unpaired electrons and the hybridisation is \[{{\operatorname{sp}}^{3}}\] (tetrahedral).