P443: One, two, many: Teaching MO theory of diatomics as a primary model of chemical bonding
Molecular orbital theory of diatomic molecules involving the 2p elements is a standard element of introductory chemistry curricula. However, it invariably follows Lewis structures as a way of understanding bonding and can often be dismissed by students as a narrowly specialized bonding model. This represents a lost opportunity, for when properly framed, MO theory of diatomics offers a clear introduction to general principles of bonding (especially the importance of orbital overlap and energy match between orbitals) that underlie bonding models in all areas and at all levels of chemistry. By repositioning it as the first bonding model presented, MO theory can serve as an introduction to simplified models such as Lewis structures and justify their successes (and failures) in a chemically sensible way. Examples of how orbital analyses of diatomics can illuminate fundamental concepts in chemical bonding will be presented, and contrasted with common textbook presentations that obscure, ignore, or misrepresent these links.