JEE Main 2026 — 21 January, Morning Shift — Question 49

A: First ionization energy generally increases across a period.

However in Period 3, $\mathrm{P} (3p^3)$ is half-filled and more stable than $\mathrm{S} (3p^4)$. Thus $\mathrm{P > S}$.

Also $\mathrm{F}$ has very high ionization energy. But $\mathrm{B}$ $\mathrm{S} (2p^1)$ has lower value.

The correct order among these should be $\mathrm{F > P > S > B}$. Thus, A is correct.

B: Electron affinity order among these is $\mathrm{Cl > F > S > P}$. Thus, B is correct.

C: Metallic character decreases from left to right and increases down the group.

Correct metallic order should be $\mathrm{K > Mg > Al > B}$. Since $\mathrm{Mg}$ is more metallic than $\mathrm{Al}$, given order $\mathrm{K > Al > Mg > B}$ is incorrect. Thus, C is incorrect.

D: Basic character of oxides increases with metallic character, and we have $\mathrm{K_2O > Na_2O > MgO > Al_2O_3}$. Since, $\mathrm{Al_2O_3}$ is amphoteric and least basic, D is correct.

Thus, the correct statements are A, B and D only.