Science, Tech, Math › Science Quick Facts About the Element Uranium Share Flipboard Email Print Z Vesoulis, Creative Commons License Science Chemistry Periodic Table Basics Chemical Laws Molecules Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated May 13, 2018 You probably know uranium is an element and that it's radioactive. Here are some other uranium facts for you. You can find detailed information about uranium by visiting the uranium facts page. 11 Uranium Facts Pure uranium is a silvery-white metal.The atomic number of uranium is 92, meaning uranium atoms have 92 protons and usually 92 electrons. The isotope of uranium depends on how many neutrons it has.Because uranium is radioactive and always decaying, radium is always found with uranium ores.Uranium is slightly paramagnetic.Uranium is named after the planet Uranus.Uranium is used to fuel nuclear power plants and in high-density penetrating ammunition. A single kilogram of uranium-235 theoretically could produce ~80 terajoules of energy, which is equivalent to the energy that could be produced by 3000 tons of coal.Natural uranium ore has been known to fission spontaneously. The Oklo Fossil Reactors of Gabon, West Africa, contain 15 ancient inactive natural nuclear fission reactors. The natural ore fissioned back at a prehistoric time when 3% of the natural uranium existed as uranium-235, which was a high enough percentage to support a sustained nuclear fission chain reaction.The density of uranium is about 70% higher than lead, but less than that of gold or tungsten, even though uranium has the second-highest atomic weight of the naturally occurring elements (second to plutonium-244).Uranium usually has a valence of either 4 or 6.Health effects of uranium typically are not related to the element's radioactivity, since the alpha particles emitted by uranium cannot even penetrate the skin. Rather, the health impact is related to the toxicity of uranium and its compounds. Ingestion of hexavalent uranium compounds can cause birth defects and immune system damage.Finely divided uranium powder is pyrophoric, meaning it will ignite spontaneously at room temperature.