question_answer

The difference in the number of unpaired electrons of a metal ion in its high spin and low-spin octahedral complexes is two. The metal ion is [JEE Main Online Paper (Held On 10-Jan-2019 Evening]

A) \[M{{n}^{2+}}\]                                

B) \[N{{i}^{2}}^{+}\]  

C) \[C{{o}^{2+}}\]         

D)                  \[F{{e}^{2}}^{+}\]

Correct Answer: C

Solution :

\[_{27}C{{o}^{+2}}=[Ar]\,3{{d}^{7}}\,4s{}^\circ \,\text{4p}{}^\circ \] No. of unpaired \[{{e}^{-}}=3\]      (For weak field ligand) \[_{27}C{{o}^{+2}}=[Ar]\,3{{d}^{7}}\,4{{p}^{0}}\] For strong field ligand No. of unpaired \[{{e}^{-}}=1\]