Question

In which of the following sets, all the species are diamagnetic in nature?

• A. $\left[ O _{2}^{2-}, O _{2}^{2+}, N _{2}^{2-}\right]$
• B. $\left[ C _{2}, O _{2}^{2-}, N _{2}^{2+}\right]$
• C. $\left[ O _{2}^{2-}, O _{2}^{+}, O _{2}^{2-}\right]$
• D. $\left[ N _{2}^{+}, O _{2}^{2+}, B _{2}\right]$

Answer 1

Answer: (B)

$C_{2}:(\sigma 1 s)^{2} < (\overset{*}{\sigma} 1 s)^{2} < (\sigma 2 s)^{2} < (\overset{*}{\sigma} 2 s)^{2}<(\pi 2 p x)^{2}=(\pi 2 p y)^{2}$

$\mu_{ eff }=0 ;$ i.e. diamagnetic

$B _{2}:(\sigma ls )^{2} < (\overset{*}{{\sigma}} 1 s )^{2} < (\sigma 2 s )^{2} < (\overset{*}{\sigma} 2 s )^{2} < (\pi 2 px )^{1} =(\pi 2 py )^{1}$

$\mu_{ eff } \neq 0 . ;$ i.e. paramagnetic

$O _{2}: (\sigma l s )^{2} < (\overset{*}{{\sigma}} 1 s )^{2} < (\sigma 2 s )^{2} < (\overset{*}{{\sigma}} 2 s )^{2} < (\sigma 2 pz )^{2} < (\pi 2 px )^{2}$

$=(\pi 2 py )^{2} < (\overset{*}{\pi} 2 p x )^{1}=(\overset{*}{\pi} 2 py )^{1}$

$O _{2}: \mu_{ eff } \neq 0$

$O _{2}^{2+}: \mu_{ eff }=0$

$O _{2}^{2-}: \mu_{ eff }=0$

$N _{2}:(\sigma l s)^{2} < (\overset{*}{\sigma} 1 s)^{2} < (\sigma 2 s)^{2} < (\overset{*}{\sigma} 2 s)^{2} < (\pi 2 p x)^{2}$

$=(\pi 2 p y)^{2} < (\sigma 2 p z)^{2}$

$N _{2}: \mu_{ eff }=0$

$N _{2}^{+}: \mu_{eff} \neq 0$

$N _{2}^{2-}: \mu_{eff} \neq 0$

$N _{2}^{2+}: \mu_{eff }=0$