Lewis dot structures are a natural extension of valence electrons and I teach both prior to teaching ions and chemical bonding in my freshmen physical science course. I teach it after discussing the make-up of the periodic table, but prior to teaching regions of the periodic table. I think it builds a nice foundation before getting to chemical bonding. In this handout, the students receive a one page description on what a Lewis dot structure is, how it relates to valence electrons, and the rules for drawing them. They then complete 22 practice diagrams.