a) Using only the valence atomic orbitals of a hydrogen atom and a fluorine atom, and following the model of Figure 9.46, how many MOs would you expect for the HF molecule?

Key Concepts

Molecular Orbitals (MOs)

Molecular orbitals are formed when atomic orbitals combine during the formation of a molecule. In the case of diatomic molecules like HF, the valence atomic orbitals of hydrogen and fluorine combine to create bonding and antibonding molecular orbitals. The number of MOs formed is equal to the sum of the atomic orbitals involved, which helps in understanding the electronic structure and stability of the molecule.

Valence Atomic Orbitals

Valence atomic orbitals are the outermost orbitals of an atom that participate in chemical bonding. For hydrogen, the valence orbital is the 1s orbital, while for fluorine, it includes the 2s and 2p orbitals. Understanding these orbitals is crucial for predicting how atoms will interact and bond to form molecules, such as HF.

Bonding and Antibonding Orbitals

In molecular orbital theory, bonding orbitals are lower in energy and stabilize the molecule, while antibonding orbitals are higher in energy and can destabilize it. When atomic orbitals combine, the resulting MOs include both types. For HF, the bonding orbital formed from the combination of hydrogen's 1s and fluorine's 2p orbitals will contribute to the molecule's stability, while any antibonding orbitals formed will have the opposite effect.