K2[NiCl4]⇒sp3, Paramagnetic
[Zn(H2O)6]Cl2⇒sp3 d2, Diamagnetic
K3[Mn(CN)6]⇒d2sp3, Paramagnetic
[Cu(PPh3)3I]⇒sp3, Diamagnetic
Hence the value of n is 2
Least value of enthalpy of atomisation among Ni ,
Zn,Mn and Cu is of Zn
$\begin{aligned}
& \mathrm{Zn}^{+2}:-[\mathrm{Ar}] 3 \mathrm{~d}^{10} \
& \mu=0
\end{aligned}$