JEE Chemistry 2025 Question with Solution

Given: The question asks which listed orbital set has the lowest energy for the hydrogen atom.

Find: The correct option.

For a hydrogen atom, the orbital energy depends only on the principal quantum number $n$. The energy is given by

So, the smaller the value of $n$, the lower (more negative) the energy.

Among the orbitals mentioned in the solution:

• $4s$ and $4p_z$ have $n = 4$
• $3p_x$, $3d_{x^2-y^2}$, and $3d_{z^2}$ have $n = 3$

Therefore, the orbitals with lower energy than the $n=4$ orbitals are the $n=3$ orbitals.

Hence, the set $(B), (C), \text{ and } (D)\text{ only}$ is supported by the worked solution.

The solution also contains a conflicting header stating The Correct Option is A. Based on the actual solution working and conclusion, the defensible answer is option B.

Given: A discrepancy exists on the solution's.

Find: Which source element should determine the answer.

The hint says that $1s$ is the lowest energy orbital for hydrogen, which is correct in general chemistry. However, $1s$ is not among the visible orbital labels discussed in the detailed solution. The detailed solution then compares the listed orbitals using the hydrogenic rule that energy depends on $n$ and concludes that the $n=3$ orbitals are lower in energy than the $n=4$ orbitals.

The step-by-step conclusion explicitly states: Therefore, the correct answer is (B), (C), and (D) only.

Since the