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)

$C_2:(\sigma 1s{)}^2<(\stackrel{\ast }{\sigma }1s{)}^2<(\sigma 2s{)}^2<(\stackrel{\ast }{\sigma }2s{)}^2<(\pi 2px{)}^2=(\pi 2py{)}^2$

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

$B_2:(\sigma ls{)}^2<(\stackrel{\ast }{\sigma }1s{)}^2<(\sigma 2s{)}^2<(\stackrel{\ast }{\sigma }2s{)}^2<(\pi 2px{)}^1=(\pi 2py{)}^1$

${\mu }_{eff}\ne 0.;$ i.e. paramagnetic

$O_2:(\sigma ls{)}^2<(\stackrel{\ast }{\sigma }1s{)}^2<(\sigma 2s{)}^2<(\stackrel{\ast }{\sigma }2s{)}^2<(\sigma 2pz{)}^2<(\pi 2px{)}^2$

$=(\pi 2py{)}^2<(\stackrel{\ast }{\pi }2px{)}^1=(\stackrel{\ast }{\pi }2py{)}^1$

$O_2:{\mu }_{eff}\ne 0$

$O_2^{2+}:{\mu }_{eff}=0$

$O_2^{2-}:{\mu }_{eff}=0$

$N_2:(\sigma ls{)}^2<(\stackrel{\ast }{\sigma }1s{)}^2<(\sigma 2s{)}^2<(\stackrel{\ast }{\sigma }2s{)}^2<(\pi 2px{)}^2$

$=(\pi 2py{)}^2<(\sigma 2pz{)}^2$

$N_2:{\mu }_{eff}=0$

$N_2^{+}:{\mu }_{eff}\ne 0$

$N_2^{2-}:{\mu }_{eff}\ne 0$

$N_2^{2+}:{\mu }_{eff}=0$