Q.
The d-electron configurations of $Cr^{2+},Mn^{2+},Fe^{2+}$ and $Co^{2+}$ are $d^4, d^5, d^6$ and $d^7$ respectively. Which one of the following will exhibit the lowest paramagnetic behaviour?
(Atomic no. $Cr=24, Mn=25, Fe=26, Co=27$).
AIEEEAIEEE 2012Coordination Compounds
Solution:
$\therefore $ Since $Co^{2+}$ has lowest no. of unpaired electrons hence lowest paramagnetic behaviour is shown by $[Co(H_2O)_6]^{2+}$
