Ions are electrically charged particles obtained from an atom or from a chemically bonded group of atoms by adding or removing electrons. Eight examples illustrate the number of protons, neutrons, and electrons in positive ions (cations) and in negative ions (anions).

Learners examine the meaning of oxidation, reduction, and half-reaction, and watch a film showing the deposition of copper metal from the reduction of copper (II) ion by aluminum. A brief quiz completes the activity.

Learners examine graphs and read that the heat of fusion is the heat energy absorbed by one mole of solid as it is converted to liquid, while the heat of vaporization is the heat energy absorbed by one mole of liquid as it is converted to gas.

Learners combine Boyle's Law and Charles's Law to solve for the pressure, volume, and temperature of a gas sample under two sets of conditions.