Question

Find out number of correct statements.
(A) $N_2>N$ ($I^{st}$ ionization energy)
(B) $O_2>O$ ($I^{st}$ ionization energy)
(C) $H_2>H$ ($I^{st}$ ionization energy)
(D) $N_2^{+}>N_2^{-}$ (Stability)
(E) $H_2>H$ ($I^{st}$ Electron Affinity)
(F) $N{a}_{2}C{O}_3>L{i}_{2}C{O}_3$ (Thermal stability)

Answer 1

(A) $N_2>N$ ($I^{st}$ ionization energy)
As $N_2=14$ electrons
Electronic configuration = $\left({\sigma }_{1s}{)}^2\right({\sigma }_{1s}^{\ast }{)}^2\left({\sigma }_{2s}{)}^2\right({\sigma }_{2s}^{\ast }{)}^2\left({\pi }_2{p}_x{)}^2\right({\pi }_{2p_y}{)}^2({\sigma }_{2p_z}{)}^2$
Electronic configuration of $N=1s^{2}2s^{2}2p^3$
As we know, removal of an electron from fully filled orbital needs more energy, so,
$N_2>N$($I^{st}$ Ionization energy)
(B) $O_2>O\left(I^{st}Ionizationenergy\right)$
$O_2=\left({\sigma }_{1s}{)}^2\right({\sigma }_{1s}^{\ast }{)}^2\left({\sigma }_{2s}{)}^2\right({\sigma }_{2s}^{\ast }{)}^2\left({\pi }_2{p}_x{)}^2\right({\pi }_{2p_y}{)}^2\left({\sigma }_{2p_z}{)}^2\right({\sigma }_{2P_z}^{\ast }{)}^2$
$O=1s^{2}2s^{2}2p^4$
As in $O_2$, electrons present in antibonding is to be removed which is loosely held as we know antibonding orbital is higher in energy than atomic orbital. Higher in energy means less stability, electrons can be removed easily
(C) $H_2>H$ ($I^{st}$ ionization energy)
$H_2=\sigma 1s^{2}H=\sigma 1s^1$
Removal of an electron from fully filled orbital is tough hence, $H_2>H$ ($I^{st}$ ionization energy)
(D) $N_2^{+}>N_2^{-}$(Stability)
B.O. of $N_2^{+}$ is 2.5
B.O. of $N_2^{-}$ is 2.5
But $N_2^{-}$ has more antibonding electrons than $N_2^{+}$ Hence, $N_2^{+}$ is more stable than $N_2^{-}$
(E) $H_2>H$ ($I^{st}$ (Electron Affinity)
$H_2=\sigma 1s^{2}H=\sigma 1s^1$
As in $H_2$ orbital is already fully filled, hence, it will be very tough to add an electron.

(F) $N{a}_{2}C{O}_3>L{i}_{2}C{O}_3$ (Thermal statulity)
$L{i}^{+}$ has an anamalously small size and very high charge density. Therefore, more polarising power. More polarized anion will decompose easily.
Hence, out of all, only $4$ statements are correct i.e., $A,C,D,F$.