Question

The d-electron configuration of $C{r}^{2+},M{n}^{2+},F{e}^{2+}$ and $C{o}^{2+}$ are $d^4,d^5,d^6$ and $d^7$ respectively. Which one of the following will exhibit minimum paramagnetic behaviour? $\left[At.no.Cr=24,Mn=25,Fe=26,Co=27\right]$

• A. ${[Fe{(H_{2}O)}_6]}^{2+}$
• B. ${[Co{(H_{2}O)}_6]}^{2+}$
• C. ${[Cr{(H_{2}O)}_6]}^{2+}$
• D. ${[Mn{(H_{2}O)}_6]}^{2+}$

Answer 1

Answer: (B)

$\therefore$ ${[Co{(H_{2}O)}_6]}^{2+}$ has minimum number of unpaired electrons and thus minimum paramagnetic behaviour.