A Russian chemist and inventor, Mendeleev is credited as being the creator of the first version of the periodic table of elements. Using the table, he predicted the properties of elements yet to be discovered.
After becoming a teacher, Mendeleev wrote the definitive textbook of his time: Principles of Chemistry (two volumes, 1868–1870). As he attempted to classify the elements according to their chemical properties, he noticed patterns that led him to postulate his periodic table. Mendeleev was unaware of the other work on periodic tables going on in the 1860s.
Mendeleev was one of the founders, in 1869, of the Russian Chemical Society. He is given credit for the introduction of the metric system to the Russian Empire.