JEE Challenger
More from Chemical Bonding and Molecular Structure
ChemMedAdv 2014 • Paper 2

Orbital Overlap Types and Characteristics Matching

Match the orbital overlap representations shown in List-I with the corresponding description provided in List-II and select the correct option using the codes given below:

List-IList-IIP.1. p−d π antibondingQ.2. d−d σ bondingR.3. p−d π bondingS.4. d−d σ antibonding\begin{array}{ll} \textbf{List-I} & \textbf{List-II} \\ \text{P.} & 1.\ p-d\ \pi\text{ antibonding} \\ \text{Q.} & 2.\ d-d\ \sigma\text{ bonding} \\ \text{R.} & 3.\ p-d\ \pi\text{ bonding} \\ \text{S.} & 4.\ d-d\ \sigma\text{ antibonding} \end{array}
Question Diagram 1

Options

A

P →\rightarrow 2, Q →\rightarrow 1, R →\rightarrow 3, S →\rightarrow 4

B

P →\rightarrow 4, Q →\rightarrow 3, R →\rightarrow 1, S →\rightarrow 2

C

P →\rightarrow 2, Q →\rightarrow 3, R →\rightarrow 1, S →\rightarrow 4

Correct
D

P →\rightarrow 4, Q →\rightarrow 1, R →\rightarrow 3, S →\rightarrow 2

Topics & Concepts

Chemical Bonding and Molecular StructureMolecular Orbital Theory

Step-by-Step Solution

To determine the correct match between the orbital overlap representations in List-I and their descriptions in List-II, we analyze the symmetry, type of orbitals involved, and the phase relationship (bonding vs. antibonding) for each representation:

  1. Analysis of Figure P:

    • Type of orbitals: Two dd-orbitals approach each other along the internuclear axis (end-on/axial overlap), which leads to a σ\sigma molecular orbital.
    • Phase of overlapping lobes: The overlapping lobes pointing toward each other have the same phase (identical shading), representing constructive overlap without a nodal plane perpendicular to the internuclear axis.
    • Conclusion: Figure P represents d−d σd-d\ \sigma bonding (P→2\textbf{P} \rightarrow \mathbf{2}).

  2. Analysis of Figure Q:

    • Type of orbitals: A two-lobed pp-orbital and a four-lobed dd-orbital overlap sideways (lateral overlap), parallel to each other. Lateral overlap results in a π\pi-type molecular orbital.
    • Phase of overlapping lobes: The lobes of the pp-orbital and the corresponding lobes of the dd-orbital that overlap have the same phase (the upper lobes share the same shade, and the lower lobes share the same shade). This constructive interference leads to a bonding interaction.
    • Conclusion: Figure Q represents p−d πp-d\ \pi bonding (Q→3\textbf{Q} \rightarrow \mathbf{3}).

  3. Analysis of Figure R:

    • Type of orbitals: A pp-orbital and a dd-orbital overlap laterally, forming a π\pi-type interaction.
    • Phase of overlapping lobes: The overlapping adjacent lobes possess opposite phases (opposite shading: upper shaded with upper unshaded, and lower unshaded with lower shaded). This destructive interference creates a nodal plane between the two nuclei perpendicular to the internuclear axis.
    • Conclusion: Figure R represents p−d πp-d\ \pi antibonding (R→1\textbf{R} \rightarrow \mathbf{1}).

  4. Analysis of Figure S:

    • Type of orbitals: Two dd-orbitals (specifically dz2d_{z^2} orbitals characterized by their central toroid/doughnut ring) overlap axially along the internuclear axis, forming a σ\sigma interaction.
    • Phase of overlapping lobes: The two main lobes facing each other along the internuclear axis have opposite phases (one is shaded, the other is unshaded), resulting in destructive interference with a nodal plane perpendicular to the bond axis.
    • Conclusion: Figure S represents d−d σd-d\ \sigma antibonding (S→4\textbf{S} \rightarrow \mathbf{4}).

Matching the pairs:

  • P→2\text{P} \rightarrow 2
  • Q→3\text{Q} \rightarrow 3
  • R→1\text{R} \rightarrow 1
  • S→4\text{S} \rightarrow 4

This matches Option (C).

PreviousNext