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
Radioactive waste these wastes must be shielded for centuries and isolated from the living environment for millennia. Since radioactive decay follows the half-life rule, the rate of decay is inversely proportional to the duration of decay. In other words, the radiation from a long-lived isotope like iodine-129 will be much less intense than that of a short-lived isotope like iodine-131. The two tables show some of the major radioisotopes, their half-lives, and their radiation yield as a proportion of the yield of fission of uranium-235. The energy and the type of the ionizing radiation emitted by a radioactive substance are also important