Q.19
According to the molecular orbital theory,
bond order for H2+ species is
Options:
(A) 0.5
(B) 1.0
(C) 1.5
(D) 2.0
Bond Order of H2+ – Molecular Orbital Theory
Molecular Orbital (MO) theory is used to explain bonding in molecules
and molecular ions. Using this theory, we can calculate the
bond order to determine the stability of a species.
Bond Order Formula
According to MO theory:
Bond Order =
(Number of bonding electrons − Number of antibonding electrons) / 2
Electronic Configuration of H2+
- Each hydrogen atom contributes 1 electron.
- H2+ has one electron removed.
- Total electrons = 1.
The single electron occupies the bonding molecular orbital
(σ1s), while the antibonding orbital (σ*1s)
remains empty.
Bond Order Calculation
Bonding electrons = 1
Antibonding electrons = 0
Bond Order = (1 − 0) / 2 = 0.5
Correct Answer
Option (A) – 0.5
Comparison Table
| Species | Bonding e− | Antibonding e− | Bond Order |
|---|---|---|---|
| H2+ | 1 | 0 | 0.5 |
| H2 | 2 | 0 | 1.0 |
Conclusion
Using molecular orbital theory, the bond order of
H2+ is found to be 0.5,
indicating a weak but stable bond.
Therefore, the correct answer is Option (A).
