JEE Main 2024 — 4 April, Shift 1 — Question 64

${{\left[ \text{V}{{\left( {{\text{H}}_{2}}\text{O} \right)}_{6}} \right]}^{3+}}\to {{\text{d}}^{2}}\text{s}{{\text{p}}^{3}}$ ${{~}_{23}}\text{ }\!\!~\!\!\text{ V}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{3}}4\text{ }\!\!~\!\!\text{ }{{\text{s}}^{2}}$ ${{\text{V}}^{+3}}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{2}},\text{n}=2$ (even number of unpaired ${{\text{e}}^{-}}$) ${{\left[ \text{Cr}{{\left( {{\text{H}}_{2}}\text{O} \right)}_{6}} \right]}^{2+}}\to \text{s}{{\text{p}}^{3}}\text{ }\!\!~\!\!\text{ }{{\text{d}}^{2}}$ ${{~}_{24}}\text{Cr}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{5}}4\text{ }\!\!~\!\!\text{ }{{\text{s}}^{1}}$ $\text{C}{{\text{r}}^{+2}}$ :- $\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{4}},\text{n}=4$

(even number of unpaired ${{\text{e}}^{-}}$)

${{\left[ \text{Fe}{{\left( {{\text{H}}_{2}}\text{O} \right)}_{6}} \right]}^{3+}}\to \text{s}{{\text{p}}^{3}}\text{ }\!\!~\!\!\text{ }{{\text{d}}^{2}}$ $\text{F}{{\text{e}}^{3+}}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{5}}4\text{ }\!\!~\!\!\text{ }{{\text{s}}^{0}}$ $\text{n}=5$ (odd number of unpaired ${{\text{e}}^{-}}$) ${{\left[ \text{Ni}{{\left( {{\text{H}}_{2}}\text{O} \right)}_{6}} \right]}^{3+}}\to \text{s}{{\text{p}}^{3}}\text{ }\!\!~\!\!\text{ }{{\text{d}}^{2}}$ $\text{Ni}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{8}}4\text{ }\!\!~\!\!\text{ }{{\text{s}}^{2}}$ $\text{N}{{\text{i}}^{+3}}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{7}},\text{n}=3$ (odd number of unpaired ${{\text{e}}^{-}}$) ${{\left[ \text{Cu}{{\left( {{\text{H}}_{2}}\text{O} \right)}_{6}} \right]}^{2+}}\to \text{s}{{\text{p}}^{3}}\text{ }\!\!~\!\!\text{ }{{\text{d}}^{2}}$ $\text{Cu}:-\left[ \text{Ar} \right]3\text{ }\!\!~\!\!\text{ }{{\text{d}}^{9}}4\text{ }\!\!~\!\!\text{ }{{\text{s}}^{0}}$ $\text{n}=1$ (odd number of unpaired ${{\text{e}}^{-}}$)