An element of the chromium group, found in certain rare minerals, as pitchblende, uranite, etc., and reduced as a heavy, hard, nickel-white metal which is quite permanent. Its yellow oxide is used to impart to glass a delicate greenish-yellow tint which is accompanied by a strong fluorescence, and its black oxide is used as a pigment in porcelain painting. Symbol U. Atomic weight 239. <--radioactive, U-235 isotope is used in atomic fission, in bombs or power plants -->
This metal is one of the heaviest of all known elements. It was named after the planet Uranus. Uranium gives off radioactivity. As it loses atomic particles, it decays and ends up, after millions of years, as lead. People working with uranium often need protective clothing to shield their bodies from radiation damage. Uranium is the fuel used to make nuclear energy in nuclear power plants. It is mined in many countries.
A rare heavy metal with an atomic number of 92. The most common atomic weight in naturally occurring uranium is 238. Other isotopes range from 234 to 239. Uranium is found in natural deposits in several parts of the world, principally as the oxide. The element was little used until about 1942 when it was discovered that Uranium-235 (the uranium isotope with an atomic weight of 235), which is present in natural uranium deposits at levels of 0.7%, could be employed as a fission fuel for the construction of nuclear reactors and weapons. This discovery led to todayis nuclear armaments and the nuclear industry.