JEE Chemistry 2026 Question with Solution

Given: Four statements compare periodic trends of first ionization energy, electron affinity, metallic character, and basic character of oxides.

Find: Which set of statements is correct.

Statement A: First ionization energy

Ionization energy generally increases across a period and decreases down a group.

The approximate values mentioned are:

Also, $P$ has the stable half-filled configuration $3p^3$, so $IE(P) > IE(S)$. Hence statement A is correct.

Statement B: Electron affinity

Electron affinity generally increases across a period, but there is an important exception between $F$ and $Cl$. Because fluorine is very small, the incoming electron faces greater repulsion, so chlorine has higher electron affinity.

Thus,

Also, $S > P$ because phosphorus has the relatively stable half-filled configuration $3p^3$. Hence statement B is correct.

Statement C: Metallic character

Metallic character decreases across a period and increases down a group. Although $K$ is the most metallic here, in period $3$ we have:

not $Al > Mg$. Therefore the order $K > Al > Mg > B$ is incorrect, so statement C is false.

Statement D: Basic character of oxides

Basic character of metallic oxides increases down a group and decreases across a period.

So,

within group $1$, and across period $3$:

where $Al_2O_3$ is amphoteric. Hence statement D is correct.

Conclusion: Statements A, B, and D are correct, while C is incorrect. Therefore, the correct option is A.

Given: The statements test periodic trends and known exceptions.

Find: Identify the correct combination.

1. For first ionization energy, the important exception used here is:

because removing an electron from $S(3p^4)$ is easier than from the half-filled $P(3p^3)$ configuration. So $F > P > S > B$ is correct.

2. For electron affinity, the important exception is:

Chlorine accommodates the incoming electron more easily than fluorine. Also,

So $Cl > F > S > P$ is correct.

3. For metallic character, the trend across period $3$ is decreasing from left to right. Therefore,

This directly shows that $K > Al > Mg > B$ is wrong.

4. For basic character of oxides, the trend follows metallic character:

So statement D is correct.

Therefore, only A, B, and D are correct. Hence the correct option is A.