curium-242 was synthesized by bombarding an isotope with alpha particles
Curium The curium-242 isotope was produced in July–August 1944 by bombarding 239Pu with α-particles to produce curium with the release of a neutron:
Atomic number All consideration of nuclear electrons ended with James Chadwick's discovery of the neutron in 1932. An atom of gold now was seen as containing 118 neutrons rather than 118 nuclear electrons, and its positive charge now was realized to come entirely from a content of 79 protons. After 1932, therefore, an element's atomic number Z was also realized to be identical to the proton number of its nuclei.