In the LCAO approximation for a homonuclear diatomic molecule, the wavefunctions for the bonding ( ψ B ) and antibonding ( ψ A ) orbitals are constructed from atomic orbitals ϕ 1 and ϕ 2 . Which state

Question

In the LCAO approximation for a homonuclear diatomic molecule, the wavefunctions for the bonding ( ψ B ) and antibonding ( ψ A ) orbitals are constructed from atomic orbitals ϕ 1 and ϕ 2 . Which statement regarding the electron density distribution is correct?

TestHub · Accepted Answer

Concept:

LCAO approximation, Probability density, Destructive vs. Constructive interference.

Solution:

1. Bonding MO: $ψ_{B} = N [ϕ_{1} + ϕ_{2}]$ . Squaring gives $∣ ψ_{B} ∣^{2} = N^{2} [ϕ_{1}^{2} + ϕ_{2}^{2} + 2 ϕ_{1} ϕ_{2}]$ .

2. The term $2 ϕ_{1} ϕ_{2}$ represents constructive interference, increasing electron density in the internuclear region.

3. (D) is incorrect because antibonding orbitals are destabilized more than bonding orbitals are stabilized due to the overlap integral $S$ .

Final Answer: Option (C)

Chemistry - CHEMICAL BONDING Question with Solution | TestHub

Options:

Doubts & Discussion