Timeline of chemical element discoveries Modern discoveries Modern discoveries

| Z | Element_ | Observed_or_predicted | Isolated_widely_known | Observer | First_isolator | Notes_ |
|---|---|---|---|---|---|---|
| 96 | Curium | 1944 |  | G. T. Seaborg, R. A. James and A. Ghiorso |  | Prepared by bombarding plutonium with alpha particles during the Manhattan Project |
| 61 | Promethium | 1942 | 1945 | S. Wu, E.G. Segrè and A. Bethe | Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin, and Harold G. Richter | It was probably first prepared in 1942 by bombarding neodymium and praseodymium with neutrons, but separation of the element could not be carried out. Isolation was performed under the Manhattan Project in 1945. |
| 97 | Berkelium | 1949 |  | G. Thompson, A. Ghiorso and G. T. Seaborg (University of California, Berkeley) |  | Created by bombardment of americium with alpha particles. |