The first ionization potentials of four consecutive elements present in the second period of the periodic table are 8.3, 11.3, 14.5 and 13.6 eV respectively. Which one of the
following is the first ionization potential (in eV) of nitrogen ?

Elements of 2nd period:  

${}_3\mathrm{Li} {}_4\mathrm{Be} {}_5 \mathrm{B} {}_6\mathrm{C} {}_7 \mathrm{N} {}_8\mathrm{O} {}_9 \mathrm{F} {}_{10}\mathrm{Ne}$

${}_7 \mathrm{N}\Rightarrow 1{ \mathrm{s}}^{2}2{ \mathrm{s}}^{2}2{\mathrm{p}}^3$

N is more electronegative among the elements. Also has a stable half-filled electron configuration due to which it will have a high first Ionization Potential but less than Ne as Ne is an inert gas. But the Ionization Potential value of Ne is more than 14.5eV due to its' inertness. 

∴ Ionization Potential of N is 14.5eV.