Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table with atomic number 92. It is assigned the chemical symbol U and naturally found as uranium-238 , uranium-235 and uranium-234.
A uranium atom has 92 protons and 92 electrons. 6 of the latter are valence electrons. The uranium nucleus binds between 141 and 146 neutrons, establishing six isotopes, the most common of which are U-238 (146 neutrons) and U-235 (143 neutrons).
Uranium has the second highest atomic weight of the naturally occurring elements; lighter only than plutonium-244 and density is about 70% higher than that of lead. It occurs naturally in low concentrations in soil, rock and water, and is commercially extracted from uranium-bearing minerals.

Applications
Military
The major application of uranium in the military sector is in high-density penetrators. This ammunition consists of depleted uranium (DU) alloyed with 1–2% other elements. At high impact speed, the density, hardness, and flammability of the projectile enable destruction of heavily armored targets. Tank armor and other, removable vehicle armor are also hardened with depleted uranium plates.
Civilian
The main use of uranium in the civilian sector is to fuel nuclear power plants. One kilogram of uranium-235 can theoretically produce about 80 trillion joules of energy (8 × 1013 joules), assuming complete fission; as much energy as 3000 tonnes of coal

History
The discovery of the element is credited to the German chemist Martin Heinrich Klaproth while he was working in his experimental laboratory in Berlin in 1789 and named the newly discovered element after the planet Uranus.
Year 1841 saw the isolation of the first sample of uranium metal by heating uranium tetrachloride with potassium. Uranium was not seen as being particularly dangerous during much of the 19th century, leading to the development of various uses for the element.
Antoine Henri Becquerel discovered radioactivity by using uranium in 1896.[10] Becquerel made the discovery in Paris by leaving a sample of a uranium salt, K2UO2(SO4)2, on top of an unexposed photographic plate in a drawer and noting that the plate had become 'fogged'.[22] He determined that a form of invisible light or rays emitted by uranium had exposed the plate