Dmitri Mendeleev (1834 - 1907)

home study in 1904

early draft of his table of elements (1869)

later revision (1871)

Institute of Weights and Measures, St. Petersburg

Mendeleev based his arrangement on atomic weight (horizontal) and similar chemical valence (e.g. same type of oxide) (vertical). Columns of elements have similar properties and reactivities. He left blanks in the table for yet to be discovered elements and even predicted their properties.

Predictions that came true by 1886:

• weight of platinum corrected
• eka-aluminum (gallium) found in 1875
• eka-boron (scandium) found in 1879
• eka-silicon (germanium) found in 1885
• position of cobalt before nickel
• position of tellurium before iodine

meyer