JEE Main 2025 — Structure Of Atom Question with Solution

Let us analyze the two statements in the context of atomic orbitals and electronic transitions:

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Statement (I)

“A spectral line will be observed for a $2p_x\to 2p_y$ transition.”

For an emission (or absorption) line to be observed, there must be a difference in energy between the initial and final states.

In a typical hydrogen-like or many-electron atom (without additional external fields or splitting effects), the three $2p$ orbitals ($2p_x$, $2p_y$, $2p_z$) are degenerate—i.e., they all have the same energy.

Consequently, a transition from $2p_x$ to $2p_y$ (both having the same energy) would involve no energy change. Hence, no photon is emitted or absorbed for this “transition.” So you would not observe a spectral line for such a transition.

Therefore, Statement (I) is false.

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Statement (II)

“$2p_x$ and $2p_y$ are degenerate orbitals.”

Orbitals within the same subshell (e.g., $2p$ subshell) are typically degenerate (same energy) in an isolated atom (especially a hydrogen-like atom).

Thus, $2p_x$ and $2p_y$ (and $2p_z$) do indeed have the same energy.

Therefore, Statement (II) is true.

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Conclusion

Statement (I): False

Statement (II): True

Hence, the correct choice is:

Option A: Statement I is false but Statement II is true.