How do you get a theorem named after you? Euler knows what it takes! The third lesson of five asks pupils to use an interactive activity to compare the faces, vertices, and edges of seven different three-dimensional solids. They use...

This essay, written for Teachers' Domain, describes the foresight and pattern recognition that Russian chemist Dmitri Mendeleyev used to develop the modern periodic table of elements.

Acting as a subtopic of the General Chemistry Virtual Textbook's section on Atoms and the Periodic Table, this site discusses the quantum revolution with special attention given to cathode rays and radioactivity.

Study the noble gases on this site. Learn about where to find them on the periodic table, what elements are in this group, and other facts.

Kids learn about the lanthanides and actinides of the periodic table. Find out which elements are in this group. properties, similarities, and other facts on this site.

ChemCenter, available from the American Chemical Society, provides chemistry news, reference sources and other public services.

Kids learn about the transition metals of the periodic table. Which elements are in this group. Properties, similarities, and other facts.

Kids learn about the nonmetals of the periodic table. Which elements are in this group. Properties, similarities, and other facts are found on this site.

On this site, investigate the alkali metals of the periodic table. Find out which elements are in this group, properties, similarities, and other facts.

Kids learn about the elements that are considered metalloids on the periodic table. This site describes the properties, similarities, and other facts.

Explore the halogens of the periodic table. Learn about which elements are in this group and the properties, similarities, and other facts.