Given below are two statements : Statement (I): A spectral line will be observed for a \(2 \mathrm{p}_{\mathrm{x}} \rightarrow 2 \mathrm{p}_{\mathrm{y}}\) transition. Statement (II): \(2 \mathrm{p}_{\mathrm{x}}\) and \(2 \mathrm{p}_{\mathrm{y}}\) are degenerate orbitals. In the light of the above statements, choose the correct answer from the options given below :

(D) Statement-I is false but Statement-II is true.

(A) Both Statement-I and Statement-II are true.

(B) Both Statement-I and Statement-II are false.

(C) Statement-I is true but Statement-II is false.

JEE Main · 2025 · 22 Jan 2025 · Shift 2 · Atomic Structure

Given below are two statements :

Statement (I): A spectral line will be observed for a

2 p_{x} \to 2 p_{y}

transition.

Statement (II):

2 p_{x}

and

2 p_{y}

are degenerate orbitals.

In the light of the above statements, choose the correct answer from the options given below :

(A)Both Statement-I and Statement-II are true.
(B)Both Statement-I and Statement-II are false.
(C)Statement-I is true but Statement-II is false.
(D)Statement-I is false but Statement-II is true.✓ Correct

Answer: (D)

Solution

A spectral line arises only from a transition between orbitals of different energy, since the photon emitted or absorbed carries away the energy difference,

Δ E = h ν

.

The

2 p_{x}

2 p_{y}

, and

2 p_{z}

orbitals are degenerate — identical in energy in the absence of an external field, differing only in spatial orientation. A transition from

2 p_{x}

2 p_{y}

therefore corresponds to

Δ E = 0

, so no photon is emitted and no spectral line is observed.

Statement I, which claims a spectral line is seen for this transition, is false. Statement II, that

2 p_{x}

and

2 p_{y}

are degenerate, is true — and it is precisely this degeneracy that rules out Statement I.

Statement I is false, but Statement II is true.

JEE Main · 2025 · 22 Jan 2025 · Shift 2 · Single correct option

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JEE Main · 2025 · 22 Jan 2025 · Shift 2 · Atomic Structure

Solution

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