1 jan 1869 ano - DMITRI MENDELEEV (1834-1907 CE)
date of discovery (1869 CE)
Created the first periodic table that
arranged the known elements according
to their of atomic mass and organized
them into groups possessing similar
properties.
His periodic table predicted the existence
of three new elements (gallium, scandium,
and germanium) and when these elements
were discovered, they fit correctly into the
three missing elements in his table.