Electrical conductivity in a solid: periodic crystal
Electrical conduction in solids - Introduction and basic theory

Most metals are crystalline solids, even if their appearance lacks the facets traditionally associated with crystals. In order to study the properties specific to their crystalline structure, we will first present the tools essential for describing crystals. We'll then look at what the crystal's periodic structure imposes on the wave function of a delocalized electron. Then we'll look at how electronic energy levels are organized into bands.