<Dd> Jacob A. Marinsky, Lawrence E. Glendenin, and Charles D. Coryell perform the first confirmed synthesis of Promethium, filling in the last "gap" in the periodic table . </Dd> <Dl> <Dt> 1945--1946 </Dt> <Dd> Felix Bloch and Edward Mills Purcell develop the process of nuclear magnetic resonance, an analytical technique important in elucidating structures of molecules, especially in organic chemistry . </Dd> </Dl> <Dt> 1945--1946 </Dt> <Dd> Felix Bloch and Edward Mills Purcell develop the process of nuclear magnetic resonance, an analytical technique important in elucidating structures of molecules, especially in organic chemistry . </Dd>

Most of the discoveries about the atom have occurred in the last 200 years