JEE Main · 2024 · Shift-IeasyBOND-097

The linear combination of atomic orbitals to form molecular orbitals takes place only when the combining atomic…

Chemical Bonding · Class 11 · JEE Main Previous Year Question

Question

The linear combination of atomic orbitals to form molecular orbitals takes place only when the combining atomic orbitals:

A. have the same energy B. have the minimum overlap C. have same symmetry about the molecular axis D. have different symmetry about the molecular axis

Options
  1. a

    A, B, C only

  2. b

    A and C only

  3. c

    B, C, D only

  4. d

    B and D only

Correct Answerb

A and C only

Detailed Solution

🧠 Linear Combination of Atomic Orbitals (LCAO) is effective only when the AOs meet specific conditions. Evaluate each:

A. Same energy: ✓ Essential — AOs with very different energies don't mix effectively.

B. Minimum overlap: ✗ Wrong — maximum overlap (not minimum) leads to effective bonding. Minimum overlap gives negligible interaction.

C. Same symmetry about the molecular axis: ✓ Essential — a σ-type AO cannot combine with a π-type AO due to symmetry mismatch (the bonding and antibonding contributions cancel).

D. Different energy: ✗ Directly contradicts condition A.

Answer: (b) A and C only\boxed{\text{Answer: (b) A and C only}}

Practice this question with progress tracking

Want timed practice with adaptive difficulty? Solve this question (and hundreds more from Chemical Bonding) inside The Crucible, our adaptive practice platform.

The linear combination of atomic orbitals to form molecular orbitals takes place only when the… (JEE Main 2024) | Canvas Classes