Question

Match the crystal field diagrams given below with the following complex ions.

${\mathbf{\left[}\mathbf{Cr}{\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}}_{\mathbf{5}}\mathbf{Cl}\mathbf{\right]}}^{\mathbf{2}\mathbf{+}}$, $$\begin{gathered} {\mathbf{\left[}\mathbf{Co}{\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}}_{\mathbf{4}}{\mathbf{Br}}_{\mathbf{2}}\mathbf{\right]}}^{\mathbf{+}} \\ \mathbf{(}\mathbf{assume}\mathbf{}\mathbf{}\mathbf{Strong}\mathbf{}\mathbf{field}\mathbf{)} \end{gathered}$$$$\begin{gathered} \mathbf{\left[}\mathbf{Fe}{\mathbf{\left(}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\right)}}_{\mathbf{6}}{\mathbf{]}}^{\mathbf{3}\mathbf{+}} \\ \right(\mathbf{Assume}\mathbf{}\mathbf{weak}\mathbf{}\mathbf{field}\mathbf{)} \end{gathered}$$

Short answer

Hence all the five electrons remain unpaired in ${\mathrm{t}}_{2\mathrm{g}}$ and ${\mathrm{e}}_{\mathrm{g}}$ orbitals as weak field is assumed.

Step-by-step solution

The electronic configuration ofFe3+ is 3d5 .

Hence all the five electrons remain unpaired in ${\mathrm{t}}_{2\mathrm{g}}$ and ${\mathrm{e}}_{\mathrm{g}}$ orbitals as weak field is assumed.

The electronic configuration of  Cr3+ is 3d3

All the three electrons are present as unpaired in${\mathrm{t}}_{2\mathrm{g}}$ orbitals of the chromium complex.

The electronic configuration of Co3+ is 3d6

All the six electrons of 3d orbitals are present as paired in ${\mathrm{t}}_{2\mathrm{g}}$orbitals of the cobalt complex.