Dmitri Ivanovich Mendeleev
Mendeleev, Dmitri Ivanovich (1834-1907), a Russian chemist. He discovered the periodic law, which states that the properties of elements are periodic functions of their atomic weights. The law was discovered independently by Julius Lothar Meyer, but Mendeleev published it first, in 1869. Mendeleev applied the law to predict correctly the existence and properties of three elements then unknown.
Mendeleev taught at the University of St. Petersburg, 1866-90, and directed Russia's bureau of weights and measures, 1893-1907. The element mendelevium is named in his honor.