Which of the following diatomic molecules is paramagnetic?

• A. F_2
• B. N_2
• C. O_2
• D. H_2

Answer: (C)

Verified step by step guidance

1. Recall that paramagnetism in molecules arises due to the presence of unpaired electrons in their molecular orbitals.
2. Write the molecular orbital electron configuration for each diatomic molecule using Molecular Orbital Theory, focusing on the valence electrons.
3. For example, consider the ordering of molecular orbitals for molecules with atomic number less than 8: \(\sigma_{2s}\), \(\sigma_{2s}^*\), \(\sigma_{2p_z}\), \(\pi_{2p_x} = \pi_{2p_y}\), \(\pi_{2p_x}^* = \pi_{2p_y}^*\), \(\sigma_{2p_z}^*\).
4. Count the number of unpaired electrons in each molecule's molecular orbital configuration. Molecules with one or more unpaired electrons are paramagnetic.
5. Identify that \(O_2\) has two unpaired electrons in its \(\pi_{2p}^*\) orbitals, making it paramagnetic, while \(F_2\), \(N_2\), and \(H_2\) have all electrons paired and are diamagnetic.