Mendeleyev, Dmitri IvanovitchMen·de·ley·ev, Dmi·tri I·van·o·vitch /ˌmendəˈleɪev, dəˈmiːtri ɪˈvɑːnəvɪtʃ/(1834–1907) a Russian scientist who invented the periodic table, which is a list of all the elements (=basic chemical substances) arranged according to their atomic number