Question

Which one of the following species doesn't have a magnetic moment of $1.73BM$, (spin only value)?

• A. $O_2^{+}$
• B. $CuI$
• C. $\left[Cu{\left(N{H}_3\right)}_4\right]C{l}_2$
• D. $O_2^{-}$

Answer 1

Answer: (B)

Species must not contain single unpaired
(1) $O_2^{+}\to {\sigma }_{1s}^2<{\sigma }_{1s}{}^{\ast 2}<{\sigma }_{2s}{}^2<{\sigma }_{2s}{}^{\ast 2}<{\sigma }_{2p}{}^2<{\pi }_{2px}{}^2={\pi }_{2py}{}^2<{\pi }_{2px}{}^{\ast }={\pi }_{2py}{}^{\ast }$
unpaired $e^{-}=1\therefore \mu =1.73BM$
(1) $C{u}^{+}{I}^{-}C{u}^{+}\to [Ar]3d^{10}$
$\therefore$ unpaired $e^{-}=0$
$I^{-}\to [Xe]$
$\therefore$ unpaired $e^{-}=0$
therefore $\mu =0$
3. $\left[Cu{\left(N{H}_3\right)}_4\right]C{l}_2$
$Cu\to [A]3d^3$
$\therefore$ unpaired $=1$
$\therefore \mu =1.73BM$
4. $O_2^{-}\to d$
${\sigma }_{1s}^2<{\sigma }_{1s}{}^{\ast 2}<{\sigma }_{2s}{}^2<{\sigma }_{2s}{}^{\ast 2}<{\sigma }_{2px}{}^2<{\pi }_{2px}{}^2={\pi }_{2py}{}^2<{\pi }_{2px}{}^{\ast }={\pi }_{2py}{}^{\ast }$
$\left(11e^{-}\right)$
$\therefore$ unpaired $\therefore \mu =1.73BM$