Glenn T. Seaborg contributed to the discovery of 11 new elements. The new elements all had atomic numbers above 92 (Uranium) and unlike previous elements discovered in the past, were synthetically made and not naturally found. In other words, these new elements were elements that did not exist naturally on earth.
1940 - Through the isolation of Uranium-233 he established thorium’s nuclear fuel potential
1944 – Seaborg formulated the “Actinide Concept”. Called one of the most significant changes to the periodic table after Mendeleev’s 19th Century Design, it showed how transuranium elements fit into the periodic table.
1944-1958 – Identified Elements 95, 96, 97, 98, 99 ,100, 102, 106