Question:medium

What is the total number of electrons present in bonding and antibonding orbitals respectively in \(\text{F}_2\) molecule according to MO theory ?

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Fill 18 electrons into the MO energy order and count those in bonding and antibonding orbitals.
Updated On: Oct 1, 2026
  • Bonding - 8, Antibonding - 10
  • Bonding - 6, Antibonding - 12
  • Bonding - 10, Antibonding - 8
  • Bonding - 12, Antibonding - 6
Show Solution

The Correct Option is C

Solution and Explanation

Step 1: Total electrons
Fluorine has $Z=9$, so the molecule has $2\times 9 = 18$ electrons.

Step 2: Use bond order
For $F_2$ the bond order is $1$. Let bonding electrons be $N_b$ and antibonding $N_a$. Then $N_b + N_a = 18$ and $(N_b - N_a)/2 = 1$.

Step 3: Solve
$N_b - N_a = 2$, so $N_b = 10$ and $N_a = 8$.
This matches the MO filling: all of the $\pi^*$ orbitals are full and $\sigma^* 2p$ is empty.

Step 4: Answer
Option (C).

Final Answer:
Bonding 10 and antibonding 8. \[ \boxed{\text{(C)}\ \text{Bonding }10,\ \text{Antibonding }8} \]
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