Which concept has supplemented the valence bond model for bond formation?

The molecular orbital model is the concept that has supplemented the valence bond model for bond formation. While the valence bond model explains bonding through the overlap of atomic orbitals to form localized bonds between pairs of atoms, the molecular orbital model provides a more comprehensive framework. It emphasizes that when atoms bond, their atomic orbitals combine to form new orbitals known as molecular orbitals, which can be spread out over multiple atoms rather than being confined between two.

This model allows for the prediction of molecular properties such as magnetism and the electronic structure of molecules more effectively than the valence bond model. In particular, it accounts for delocalized electrons in systems like benzene, where electrons are not localized in individual bonds but are shared across the entire molecule, providing a deeper understanding of stability and reactivity in molecular systems.

Understanding the molecular orbital model enhances our comprehension of chemical bonding beyond the limitations of the valence bond approach, making it an essential addition to the study of chemical bonding and molecular geometry.