To determine the bond order of
HeH+, we can use the bond order formula:
Bond Order
=‌where:
Nb is the number of electrons in bonding molecular orbitals.
Na is the number of electrons in antibonding molecular orbitals.
Here's how we can break it down:
Count the electrons:
Helium (He) normally has 2 electrons.
Hydrogen
(H) has 1 electron.
Since the molecule is
HeH+, one electron is removed from the total count.
Total electrons
=2+1−1=2 electrons.
Form the molecular orbitals:
When the 1 s orbitals of He and H combine, they form a bonding orbital
(σ1s) and an antibonding orbital
(σ1s*).
With only 2 electrons available, both electrons will occupy the lower-energy bonding orbital (
σ1s), leaving the antibonding orbital empty.
Calculate the bond order:
Number of electrons in bonding orbitals,
Nb=2.
Number of electrons in antibonding orbitals,
Na=0.
Plugging into the formula:
Bond Order
=‌=1Therefore, the bond order of
HeH+is 1.
The correct answer is Option A: 1.