What does molecular orbital theory describe?

Molecular orbital theory provides a framework for understanding how atomic orbitals combine to form molecular orbitals, which can be occupied by electrons in a molecule. This theory describes the process through which atomic orbitals from different atoms overlap and interact, leading to the formation of bonding and antibonding molecular orbitals. These molecular orbitals are integral in determining the electronic structure, stability, and properties of molecules.

Through molecular orbital theory, we can predict characteristics such as bond order, magnetic properties, and even the energy levels of electrons within a molecule. By focusing on the overlap of atomic orbitals, molecular orbital theory dives deeper than simple valence bond theory, allowing for a more comprehensive understanding of chemical bonding and molecular geometry.

The other options do not pertain directly to the concept of molecular orbital theory. Predicting boiling points is more associated with intermolecular forces and molecular size. Electronegativity principles involve the ability of an atom to attract electrons, while gas behavior under pressure relates to the physical laws governing gases, such as Boyle's law. These concepts, while important in chemistry, do not explain how molecular orbitals are created and utilized in bonding within molecules.