In this screencast, students read about the basic organization and structure of the periodic table of elements. Students identify elements as belonging to a group, a period, or neither.

In this animated activity, learners examine the terms "half-reaction," "oxidizing agent," and "reducing agent" and follow five interactive examples to balance equations for oxidation-reduction reactions. Three problems are provided as a self-check.

In this screencast, learners examine the kinds of physical and chemical changes that occur in substances.

In this animated and interactive object, learners follow two rules to write unit conversion fractions.