See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

(A) Periodic property of ionization enthalpy (B)    + Al g Al g Δ H ion 1   ++ Al g   +++ Al g Δ H ion 2 Δ H ion 3   2 1 3s 3p unstable 2 o 3s 3p   1 3s unstable o 3s and (C)    + Mg g Mg g Δ H ion 1   ++ Mg g   +++ Mg g Δ H ion 2 Δ H ion 3   2 3s stable 1 3s   6 2 2s stable 2p 2 5 2s 2p (D)   + N N g g Δ H ion 1  ++ N  g Δ H ion 2 2 3 2s 2p   2 2 2s 2p unstable    + O O g g Δ H ion 1  ++ O  g Δ H ion 2 2 4 2s 2p   2 3 2s 2p stable