JEE Main 2026 — Apr 5, Shift 1 — Chemistry solution

JEE Main2026Apr 5, Shift 1Chemistry

Identify the correct statements from the following :

A. Heisenberg uncertainty principle is applicable to electron.

B. The size of $2 p_{x}$ orbital is less than the size of $3 p_{x}$ orbital.

C. The energy of $2 s$ orbital of H atom is equal to the energy of $2 s$ orbital of Li.

D. The electronic configuration of Cr is [Ar] $3 d^{5} 4 s^{1}$ .

Choose the correct answer from the options given below :

A
A, B and C only
B
A, B and D only
C
B, C, and D only
D
A, C and D only

Solution

A: The uncertainty principle applies to every microscopic particle, including electrons. Correct.

B: Orbital size increases with principal quantum number, so $2 p_{x} < 3 p_{x}$ . Correct.

C: Orbital energies in multi-electron atoms depend on nuclear charge and shielding; Li differs from H, so $E_{2 s} (H) \neq = E_{2 s} (Li)$ . Incorrect.

D: The anomalous configuration $[Ar] 3 d^{5} 4 s^{1}$ is correct because a half-filled $3 d$ subshell adds extra stability. Correct.

Correct set: A, B, and D.

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