This document is about the periodic table and chemical bonds. It contains the following key points: 1) The smallest period is the first period, which contains only hydrogen and helium. The number of periods corresponds to the number of electron shells in the atoms. 2) The lanthanides (elements after lanthanum) and actinides (elements after actinium) are not in the same row, but are called inner transition elements. Most actinides are artificial elements. 3) The review questions ask the student to determine period, group, and other properties based on given electronic configurations of elements.