The Periodic Law of Chemistry, often portrayed as a table, "The Periodic Table of the Elements," is an introduction to the similarities and differences in the behavior of elements. (When the window with the table opens, click on the page to enlarge the table.)
The Chemical Heritage Foundation combines information about the history and practice of chemistry. This includes recent and current events; information about a museum and library with their collections; fellowships or scholarships and more. The foundation is located nearby in Philadelphia.