Question

Assertion : Fluorine molecule has bond order one.
Reason : The number of electrons in the antibonding molecular orbitals is two less than that in bonding molecular orbitals.

• A. Both Assertion and Reason are true and Reason is a correct explanation of the Assertion
• B. Both Assertion and Reason are true but Reason is not a correct explanation of the Assertion
• C. Assertion is true but Reason is false
• D. Both Assertion and Reason are false
• E. Assertion is false but Reason is true

Answer 1

Answer: (A)

Both Assertion and Reason are true and Reason is a correct explanation of the Assertion

$MO$ electronic configuration of $F_2$ molecule is as follows:

$\sigma 1s^2,{\sigma }^{\ast }1s^2,\sigma 2s^2,{\sigma }^{\ast }2s^2,\sigma 2p_x^2,\pi 2p_y^2\approx \pi 2p_z^2,{\pi }^{\ast }2p_y^2\approx {\pi }^{\ast }2p_z^2$
Thus, there are $10$ electrons in bonding orbitals and $8$ electrons in antibonding orbitals. Thus, reason is true and it is also the correct explanation of assertion because bond order $=\frac{N_b-N_a}{2}=\frac{10-8}{2}=1$