S2.2 (AHL) The covalent model (1)
This is the first part of the Additional Higher Level material on S2.2 The covalent model. It covers the concept of resonance hybrids using benzene as a specific example, and also the concept of formal charge to determine the preferred Lewis formula from several possibilities. The ability of some atoms, such as phosphorus and sulfur, to expand their octet when they bond together with the shapes and polarities of the...