Question

The number of anti-bonding electron pairs in O⁻²₂ molecular ion
on the basis of molecular orbital theory is, (Atomic number of O is 8)
(a) 5 (b) 2
(c) 3 (d) 4

Answer 1

Explanation:

b 2 ..................I think

Answer 2

The number of anti-bonding electron pairs in O₂⁻² molecular ion is (d) 4

Explanation:

The electronic configuration of O₂⁻² molecular ion is given as:

O₂⁻² (18) → (σ1s)², (σ*1s)² (σ2s)², (σ*2s)² (σ2px)², (π2py)², (π2pz)², (π*2py)², (π*2pz)²

The number of anti-bonding in O₂⁻² molecular ion is given as:

⇒ (σ*1s)², (σ*2s)², (π*2py)², (π*2pz)²

⇒ 8 × (4 pairs)

Thus, the number of pairs is 4.