Dmitri Mendeleev
Unaware of the earlier work on periodic tables going on in the 1860s, he made the following table:
By adding additional elements following this pattern, Mendeleev developed his extended version of the periodic table. On 6 March 1869, he made a formal presentation to the Russian Chemical Society, titled "The Dependence between the Properties of the Atomic Weights of the Elements", which described elements according to both atomic weight (now called "relative atomic mass") and valence. This presentation stated that
Dmitri Mendeleev
Mendeleev published his periodic table of all known elements and predicted several new elements to complete the table in a Russian-language journal. Only a few months after, Meyer published a virtually identical table in a German-language journal. Mendeleev has the distinction of accurately predicting the qualities of what he called ekasilicon, ekaaluminium and ekaboron (germanium, gallium and scandium, respectively).