Final answer:
The correct characterization for the molecular orbitals of B₂, C₂, and N₂ is significant mixing between the 2s and 2p atomic orbitals. This mixing is part of the molecular orbital theory that provides the bonding description for these molecules, and the energy arrangement for these diatomic molecules indicates such hybridization.
Step-by-step explanation:
The statement that accurately characterizes the molecular orbitals of B₂, C₂, and N₂ is: They exhibit significant mixing between the 2s and 2p atomic orbitals. This molecular orbital theory explains the energy and bonding properties of these diatomic molecules. The mixing of 2s and 2p orbitals leads to hybridization, which provides the correct description of the bonding in these molecules.
In the context of molecular orbital theory, for period 2 diatomic molecules such as B₂, C₂, and N₂, the σ2p molecular orbital is slightly higher in energy than the π and π⁴ molecular orbitals. This is true for these diatomic molecules to the left of N₂ in the periodic table, and this energy arrangement leads to the molecular orbitals exhibiting significant s and p character mixing. This mixing of orbitals, or hybridization, helps to explain the structures and properties of these molecules effectively.
Finally, the way hybrid orbitals overlap to form sigma bonds and unhybridized orbitals overlap to form pi bonds is important in understanding these molecules' bonding and structure. However, it is important to note that while hybridization is useful for explaining bonding, there are limitations to the model and it is not universally accepted.