jan 1, 1905 - 1905 - Discovery of "radiothorium"
Hahn discovers "radiothorium", which is now
known as thorium-x, an isotope of thorium. An
isotope is a variant of an element with a
different number of neutrons, but the same
number of protons and electrons as that
element. This discovery was made while working alongside Sir William Ramsay at University College in London.
