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.

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 well-illustrated activity, learners examine the three types of intermolecular forces: dipole-dipole forces, London or Van der Waals forces, and the hydrogen bond. Two interactive questions are included.

Learners use the coefficients in a balanced equation to develop the mole ratios of reactants and products involved in the reaction. Five interactive examples illustrate the method, and students test their knowledge by working four problems.

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.

Students read about the basic organization and structure of the periodic table of elements. By clicking on the symbol, they can read that element's atomic number and weight. In an exercise, students identify elements as belonging to a group, a period, or neither.

Students read an introduction to the lab equipment used to contain and dispense chemicals. A quiz completes the activity.

In this highly interactive object, learners examine the internal elements of a 555 IC and their operation. Learners then test their knowledge in a variety of exercises.

Learners examine the elements of a data file memory of an Allen-Bradley SLC-500 programmable controller. A quiz completes the activity.

Review important vocabulary about chemical reactions.

Review the difference between chemical and physical changes.

Carbon is Everywhere

Chemistry - Atomic Radius