Uranium tile Uranium tile Uranium tiles have been used in the ceramics industry for many centuries, as uranium oxide makes an excellent ceramic glaze, and is reasonably abundant on the earth's crust. Not long after Henri Becquerel discovered radioactivity in uranium salts, Madame Curie discovered both polonium and radium as two new radioactive elements also present with uranium. The relatively high specific activity and moderate half-life of 1,600 years of Ra-226, the main radioisotope of radium found in uranium ore, made for a material which when mixed with a phosphor allowed for a glow-in-the-dark substance. Thus, in addition to its medical usage,
Period 5 element and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature. Naturally occurring technetium occurs as a spontaneous fission product in uranium ore or by neutron capture in molybdenum ores. The chemical properties of this silvery gray, crystalline transition metal are intermediate between rhenium and manganese. Many of technetium's properties were predicted by Dmitri Mendeleev before the element was discovered. Mendeleev noted a gap in his periodic table and gave the undiscovered element the provisional name "ekamanganese"