$(b)\,\mathop C\limits_{2{p^2}}  \to \mathop {{C^ + }}\limits_{2{p^1}}  \to C_{2{s^2}}^{2 + }$   $\mathop N\limits_{2{p^3}}  \to \mathop {{N^ + }}\limits_{2{p^2}}  \to \mathop {{N^{2 + }}}\limits_{2{p^1}} $   $\mathop O\limits_{2{p^4}}  \to \mathop {{O^ + }}\limits_{2{p^3}}  \to \mathop {{O^{2 + }}}\limits_{2{p^2}} $

$(c)\,\mathop F\limits_{2{p^5}} \xrightarrow{{I.E{._1}}}\mathop {{F^ + }}\limits_{2{p^4}} \xrightarrow{{I.E{._2}}}\mathop {{F^{2 + }}}\limits_{2{p^3}} \xrightarrow{{I.E{._3}}}{F^{3 + }}$   $\mathop O\limits_{2{p^4}} \xrightarrow{{I.E{._1}}}\mathop {{O^ + }}\limits_{2{p^3}} \xrightarrow{{I.E{._2}}}\mathop {{O^{2 + }}}\limits_{2{p^2}} \xrightarrow{{I.E{._3}}}{O^{3 + }}$

$(d)$ In respective period, noble gases have highest $I.E.$