Russian chemist Dmitri Mendeleev (also Dmitrii Mendeleyev) created the first valid periodic table of the elements in 1869. With the exception of post-graduate training in England and Germany (where he studied with Robert Wilhelm Bunsen), Mendeleev spent most of his career in St. Petersburg (Leningrad) as a popular and influential lecturer at the university. He created a table of the known elements (63 at the time) in ascending order by atomic weight, grouped together by similarities in properties. Mendeleev's particular genius was to leave gaps for elements not yet discovered. By the 1880s some of those element had been discovered, vindicating Mendeleev and making him famous in and out of Russia. He resigned his post at the University of St. Petersburg in 1893 and became the director St. Petersburg's bureau of weights and measures.
Information about Mendeleev’s early years is scant; some sources list his birthday as 8 February… As part of his interest in aeronautics, he made a solo ascent in a hot air balloon in 1887… In 1955 the element mendelevian (element 101) was named to honor him.