Johann Wolfgang Döbereiner (TRIADS; he placed three elements into groups called triads) (jan 1, 1829 – aug 9, 1829)
Description:
He placed various groups of three elements into groups called triads. One such triad was lithium, sodium, and potassium. Triads were based on both physical, as well as chemical, properties.Added to timeline:
Date:
jan 1, 1829
aug 9, 1829
~ 7 months