Question

The total number of anti bonding molecular orbitals, formed from 2s and 2p atomic orbitals in a diatomic molecule is _____________.

Answer 1

Correct Answer: 4

Atomic orbital combination in diatomic molecules yields both bonding and anti-bonding molecular orbitals. Specifically, for atomic orbitals 2s and 2p:

• 2s orbital combination: Overlap of two 2s orbitals produces one bonding (σ_2s) and one anti-bonding (σ_2s^*) molecular orbital.
• 2p orbital combination: The 2p orbitals divide into three types: σ and two π orbitals. These form bonding and anti-bonding combinations:
  • σ_2p orbitals: Generate one σ_2p and one σ_2p^* orbital.
  • π_2p orbitals: Each pair creates two degenerate π_2p and π_2p^* orbitals. With two pairs, this results in two bonding π_2p orbitals and two antibonding π_2p^* orbitals.

Total anti-bonding orbitals:

• From 2s: One σ_2s^* orbital.
• From 2p: One σ_2p^* and two π_2p^* orbitals.

The total count of anti-bonding orbitals is 1 (from 2s) + 1 (from σ_2p^*) + 2 (from 2 π_2p^*) = 4. This sum of 4 is within the specified range of (4,4).