Dmitry Ivanovich Mendeleyev

Born in Tobolsk, Siberia, in 1834, Dmitri Ivanovich Mendeleev became one of the most influential chemists of the 19th century. He taught in St. Petersburg and wrote the widely used textbook Principles of Chemistry, building a reputation as a gifted teacher as well as a researcher.

Mendeleev is most famous for formulating the periodic law and creating a table that arranged the known elements in a meaningful pattern. What made his approach remarkable was that he left gaps for elements not yet discovered and predicted their properties in advance, a move that gave his system lasting authority when later discoveries matched his forecasts.

His interests reached beyond the periodic table. He also worked on questions in physics, chemistry, and measurement, and later served as director of Russia’s bureau of weights and measures. He died in St. Petersburg in 1907, but his name remains closely tied to one of science’s most elegant organizing ideas.