Element collecting from hydrogen to bismuth (except the radioactive technetium and promethium) are collected, with the exceptions of the extremely long-lived thorium and uranium. It is possible to source other radioactive elements, such as radium (usually in the form of radium sulphate as part of luminescent paint on antique watch hands), tritium - a radioactive isotope of hydrogen, americium (in the form of radioactive buttons containing 0.29 micrograms of americium extracted from older smoke detectors), and technetium. Element collecting Element collecting is the hobby of collecting the chemical elements. Many element collectors simply enjoy finding peculiar uses of chemical elements. Others enjoy
Stephanie Horovitz radiochemistry. It predicted that lead resulting from the radioactive decay of uranium or thorium would have different atomic weights than typical lead. Early experimental data was not considered authoritative by analytical chemists. Hönigschmid had studied under leading expert Theodore Williams Richards at Harvard and his work in determining precise atomic weights was well respected. Horovitz isolated lead from uranium-rich pitchblende samples from the St. Joachmistal mine. Her gravimetric analysis to the thousandth of a gram proved that lead created from the radioactive decay of uranium had a lower atomic weight than typical lead. This was the first widely-accepted experimental proof