Johann Wolfgang Döbereiner (1780–1849) (dec 13, 1780 – mar 24, 1849)
Description:
Johann Wolfgang Döbereiner, who was born in Germany, contributed to the classification of elements by identifying "triads," groups of three elements with similar properties (e.g., lithium, sodium, potassium), which foreshadowed the periodic table's development and the idea of periodicity in element properties. In 1823, his experiments showed that in each triad the mean of the lightest and heaviest atomic weights approximated the atomic weight of the middle element. But he could not substantiate his hypothesis with a sufficient number of triads, and his findings were regarded in his time as merely interesting curiosities. Johann Wolfgang Döbereiner helped for later developments in the periodic table, influencing chemists like Dmitri Mendeleev.Added to timeline:
Date:
dec 13, 1780
mar 24, 1849
~ 68 years