In this interactive lesson, students examine the quantitative relationship between chemicals in a balanced mathematical equation.

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

Students read brief descriptions of atoms, molecules, elements, and compounds, and complete a matching exercise that pictures these particles and molecules as pieces of taffy.

In this animated and interactive object, learners observe how two, three, or four groups of electrons around the central atom cause the shape of the molecule to be linear, trigonal planar, bent, tetrahedral, or pyramidal. Seven examples and eight interactive questions are provided.