Uranium is the fourth member of the actinides located on the second row below the periodic table. It is a silvery-gray, radioactive metal with a melting point of 1132 degrees Celsius. It was discovered in 1789 by Martin Klaproth. It is a reactive metal that quickly forms oxides on exposure to air. Uranium 238 and 235 have half-lives of 4.5 billion and 700 million years respectively. 

One of Uranium's most notorious uses is in nuclear weapons. Luckily, Uranium has more positive uses. An example of this is in nuclear power plants, where Uranium-235 undergoes fission to produce energy. Uranium is also used to make heavier elements such as Neptunium and Plutonium.