Uranium (pronounced /jʊˈreɪniəm/ yoo-RAY-nee-əm) is a silvery-white metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. Besides its 92 protons, a uranium nucleus can have between 141 and 146 neutrons. The most common uranium isotopes are U-238 (146 neutrons) and U-235 (143 neutrons). A uranium atom has 92 electrons, 6 of them valence electrons. Uranium has the highest atomic weight of...
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Uranium (pronounced /jʊˈreɪniəm/ yoo-RAY-nee-əm) is a silvery-white metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. Besides its 92 protons, a uranium nucleus can have between 141 and 146 neutrons. The most common uranium isotopes are U-238 (146 neutrons) and U-235 (143 neutrons). A uranium atom has 92 electrons, 6 of them valence electrons. Uranium has the highest atomic weight of the naturally occurring elements. It is about 70% denser than lead, but not as dense as gold or tungsten. Uranium is weakly radioactive. It occurs naturally in low concentrations (a few parts per million) in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite (see uranium mining).
In nature, uranium atoms exist as uranium-238 (99.284%), uranium-235 (0.711%), and a very small amount of uranium-234 (0.0058%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is...
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