Chemical Bonding and Molecular Structure Part 2

Those species which have unpaired electrons are called paramagnetic species.And those species which have no unpaired electrons are called diamagnetic species. (1) $\mathrm{N}_2$ has 14 electrons.Moleculer orbital configuration of $\mathrm{N}_2$$= \sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \sigma_{2 p_{z}^{2}}$Here no unpaired electron present, so it is diamagnetic.(2) Moleculer orbital configuration of $\mathrm{N}_2^{+}$(13 electrons)$= \sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \sigma_{2 p_{z}^{1}}$Here in $\mathrm{N}_2^{+}, 1$ unpaired electron present, so it is paramagnetic.(3) $\mathrm{N}_2^{2-}$ has 16 electrons. Moleculer orbital configuration of $\mathrm{N}_2^{2-}$ is$\sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \sigma_{2 p_{z}^{2}} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \pi_{2 p_{x}^{1}}^{*} = \pi_{2 p_{y}^{1}}^{*}$Here 2 unpaired electron present, so it is paramagnetic.(4) $\mathrm{N}_2^{-}$has 15 electrons.Moleculer orbital configuration of $\mathrm{N}_2^{-}$is$\sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \sigma_{2 p_{z}^{2}} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \pi_{2 p_{x}^{1}}^{*} = \pi_{2 p_{y}^{0}}^{*}$Here 1 unpaired electron present, so it is paramagnetic.(a) $\mathrm{O}_2^{2-}$ has 18 electrons. Moleculer orbital configuration of $\mathrm{O}_2^{2-}$ is$\sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \sigma_{2 p_{z}^{2}} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \pi_{2 p_{x}^{2}}^{*} = \pi_{2 p_{y}^{2}}^{*}$Here is no unpaired electron so it is diamagnetic.(b) $\mathrm{O}_2^{-}$has 17 electrons.Moleculer orbital configuration of $\mathrm{O}_2^{2-}$ is$\sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \sigma_{2 p_{z}^{2}} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \pi_{2 p_{x}^{2}}^{*} = \pi_{2 p_{y}^{1}}^{*}$Here 1 unpaired electron present, so it is paramagnetic.(c) $\mathrm{O}_2$ has 16 electrons. Moleculer orbital configuration of $\mathrm{O}_2$ is$\sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \sigma_{2 p_{z}^{2}} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \pi_{2 p_{x}^{1}}^{*} = \pi_{2 p_{y}^{1}}^{*}$Here 2 unpaired electron present, so it is paramagnetic.(d) $\mathrm{O}_2^{+}$has 15 electrons.Moleculer orbital configuration of $\mathrm{O}_2^{+}$is$\sigma_{1 s^{2}} \sigma_{1 s^{2}}^{*} \sigma_{2 s^{2}} \sigma_{2 s^{2}}^{*} \sigma_{2 p_{z}^{2}} \pi_{2 p_{x}^{2}} = \pi_{2 p_{y}^{2}} \pi_{2 p_{x}^{1}}^{*} = \pi_{2 p_{y}^{0}}^{*}$Here 1 unpaired electron present, so it is paramagnetic.