NEETChemistryChemical Bonding and Molecular Structure
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The O ₂ molecule is paramagnetic because its highest occupied molecular orbitals are ^ * _ 2p_x and ^ * _ 2p_y , each containing one electron. Reason (R): In the O ₂ molecule, the energy of the _ 2p_z molecular orbital is higher than that of the _ 2p_x and _ 2p_y orbitals. In the light of the above
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
C. (A) is true but (R) is false
Step-by-step solution
The O ₂ molecule has 16 electrons. Its molecular orbital electronic configuration is: _ 1s ^2 ^ * _ 1s ^2 _ 2s ^2 ^ * _ 2s ^2 _ 2p_z ^2 _ 2p_x ^2 = _ 2p_y ^2 ^ * _ 2p_x ^1 = ^ * _ 2p_y ^1 The highest occupied molecular orbitals are ^ * _ 2p_x and ^ * _ 2p_y , each containing one unpaired electron. The presence of these unpaired electrons makes the O ₂ molecule paramagnetic. Thus, Assertion (A) is true. For molecules with more than 14 electrons (like O ₂ and F ₂ ), the 2s - 2p mixing is negligible. As a result, the