Learners assign oxidation numbers to atoms in neutral compounds and in polyatomic ions. Six examples are worked through in detail, and three problems are provided.

Learners examine the method used to calculate the mass percent of an element in a compound. Three examples and one problem illustrate the method.

In this screencast, we review the positions of metals, metalloids, and nonmetals in the Periodic Table and the general characteristics of each.

In this colorful, interactive object, learners examine how materials on the nanoscale compare with those on the macroscale. The focus is on the difference between macroscale and nanoscale gold in both color and melting point.