Question

What is the number of electrons in bonding molecular orbitals and antibonding molecular orbitals respectively in \(\text{F}_{2}\) molecule?

• A. 12 and 6
• B. 10 and 8
• C. 8 and 10
• D. 6 and 12

Hint:

Fill the 18 electrons of F2 into molecular orbitals in order and count those in bonding and antibonding orbitals.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
Each F atom has 9 electrons, so \(\text{F}_2\) has 18 electrons to place in molecular orbitals.

Step 2: MO Configuration
\(\sigma1s^{2}\,\sigma^{*}1s^{2}\,\sigma2s^{2}\,\sigma^{*}2s^{2}\,\sigma2p_z^{2}\,\pi2p_x^{2}\pi2p_y^{2}\,\pi^{*}2p_x^{2}\pi^{*}2p_y^{2}\)

Step 3: Count the electrons
Bonding: \(2+2+2+4=10\).
Antibonding: \(2+2+4=8\).

Step 4: Check
Bond order \(=\dfrac{10-8}{2}=1\), which matches the single F-F bond.

Final Answer:
\(\text{F}_2\) has 10 bonding and 8 antibonding electrons. \[ \boxed{\text{(B) }\text{10 and 8}} \]