Prefer Newsweek on Google to see more of our trusted coverage when you search. The periodic table stares down from the walls of just about every chemistry lab. The credit for its creation generally ...

A century and a half ago, a Russian chemistry professor published a classification of all the known elements, organized by atomic weight. Today, the system that he created for his students — plus some ...

At the middle of the 19th century, 63 chemical elements were known to science. Before Mendeleev’s discovery, attempts at arranging them in some logical way were made by Johann Doebereiner (1829), ...