Work by Henri Becquerel, Marie Curie, Pierre Curie, and Rutherford further elaborated that the nucleus, though tightly bound, could undergo different forms of radioactive decay, and thereby transmute into other elements.
Arbejder af Henri Becquerel, Marie Curie, Pierre Curie, og Rutherford viste yderligere at kernen, selvom den er tæt bundet, kunne gennemgå forskellige former for radioaktivt henfald, og derved transmutere til andre grundstoffer.