Chemistry - PERIODIC TABLE Question with Solution | TestHub

(A) As removal of second electron takes place from half filled valence shell electron configuration of ${\mathrm{O}}^{+}$ i.e. $2{\mathrm{s}}^{2}2{\mathrm{p}}^3$.

(B) I.E(III) of ${}_{13}\mathrm{Al}$ is $2744\mathrm{kJ}{\mathrm{mol}}^{-1}$ where as that of ${}_{15}\mathrm{P}$ is $2910\mathrm{kJ}\mathrm{mol}{}^{-1}$. This is because of higher nuclear charge in phosphorus.

(C) I.E(I) of Al is $577\mathrm{kJ}{\mathrm{mol}}^{-1}$ and that of Ga is $579\mathrm{kJ}{\mathrm{mol}}^{-1}$. This may be because of their similar sizes i.e. $1.25\mathring{A}$ in both.

(D) ${}_5{\mathrm{B}}^{+}=1{\mathrm{s}}^{2}2{\mathrm{s}}^2;{}_6{\mathrm{C}}^{+}=1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^1$; As s-sub shell electron has high penetration power than p-sub shell electron. In addition ${\mathrm{B}}^{+}$has completely filled 2s sub shell. So I.E (II) of B is 2427 and that of C is 2354 $\mathrm{kJ}{\mathrm{mol}}^{-1}$.