jan 7, 1940 - Current Periodic Table
Description:
The last major change to the periodic table was made by Glenn Seaborg in 1951. In 1941, he discovered plutonium and then continued to discover all the transuranic elements from 94 to 102. He reconfigured the periodic table by placing the actinoid series below the lanthanoid series at the bottom of the table.
Added to timeline:
History of the Periodic Table - 10
Date:
