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Question #44266

Difficulty: 8/10 | 🟢 Free

The Question

An electron in a hydrogenic ion is excited to a stationary state characterized by the wavefunction ψ(r,θ,ϕ)\psi(r, \theta, \phi). Analysis of the probability density ∣ψ∣2|\psi|^2 reveals exactly one radial (spherical) node and zero electron density on the mutually perpendicular planes defined by the equations x=0x = 0 and z=0z = 0. Assuming the standard quantum mechanical convention mapping real dd-orbitals to magnetic quantum numbers (ml=0m_l = 0 for dz2d_{z^2}, ml=±1m_l = \pm 1 for dxz,dyzd_{xz}, d_{yz}, and ml=±2m_l = \pm 2 for dxy,dx2−y2d_{xy}, d_{x^2-y^2}), which of the following correctly identifies the principal, azimuthal, and magnetic quantum numbers (n,l,ml)(n, l, m_l) for this state, along with the geometric axis where its planar nodes intersect?

Options

  • A.

    (4,2,±1)(4, 2, \pm 1) ; Intersection axis is the yy-axis

  • B.

    (4,2,±1)(4, 2, \pm 1) ; Intersection axis is the xx-axis

  • C.

    (4,2,±2)(4, 2, \pm 2) ; Intersection axis is the zz-axis

  • D.

    (3,2,±1)(3, 2, \pm 1) ; Intersection axis is the yy-axis

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Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Pauli Exclusion Principle|Angular Nodes and Planar Nodes

Why This Question Is Tricky

Common Mistakes

This question tests the deep geometric understanding of quantum numbers and nodal planes.

Students often memorize that dd-orbitals have 2 planar nodes but fail to map the specific plane equations (x=0,z=0x=0, z=0) to the correct real orbital (dxzd_{xz}).

A common trap is assuming that because the nodes are defined by xx and zz, the orbital must be dyzd_{yz} (leading to Option B), or miscalculating the radial nodes by forgetting the formula n−l−1n-l-1 (leading to Option D).

Furthermore, it tests the spatial visualization of intersecting planes to identify the correct axis of zero electron density.

Quick Facts About This Question

Question Information

SubjectChemistry
ChapterStructure of Atom - Class 11 Part 1
ConceptPauli Exclusion Principle
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree