Uranium is a chemical element in the periodic table that has the symbol U and atomic number 92. Heavy, silvery-white, toxic, metallic , and naturally- radioactive , uranium belongs to the actinide series and its isotope 235 U is used as the fuel for nuclear reactors and the explosive material for nuclear weapons. Uranium is commonly found in very small amounts in rocks , soil , water , plants , and animals (including humans).
When refined, uranium is a silvery white, weakly radioactive metal, which is slightly softer than steel. It is malleable, ductile, and slightly paramagnetic. Uranium metal has very high density , 65% more dense than lead , but slightly less dense than gold. When finely divided, it can react with cold water; in air, uranium metal becomes coated with uranium oxide. Uranium in ores can be extracted and chemically converted into uranium dioxide or other chemical forms usable in industry.