<P> Uranium is a chemical element with symbol U and atomic number 92 . It is a silvery - white metal in the actinide series of the periodic table . A uranium atom has 92 protons and 92 electrons , of which 6 are valence electrons . Uranium is weakly radioactive because all isotopes of uranium are unstable , with half - lives varying between 159,200 years and 4.5 billion years . The most common isotopes in natural uranium are uranium - 238 ( which has 146 neutrons and accounts for over 99 % ) and uranium - 235 ( which has 143 neutrons ) . Uranium has the highest atomic weight of the primordially occurring elements . Its density is about 70 % higher than that of lead , and slightly lower than that of gold or tungsten . It occurs naturally in low concentrations of a few parts per million in soil , rock and water , and is commercially extracted from uranium - bearing minerals such as uraninite . </P>
<P> Uranium is a chemical element with symbol U and atomic number 92 . It is a silvery - white metal in the actinide series of the periodic table . A uranium atom has 92 protons and 92 electrons , of which 6 are valence electrons . Uranium is weakly radioactive because all isotopes of uranium are unstable , with half - lives varying between 159,200 years and 4.5 billion years . The most common isotopes in natural uranium are uranium - 238 ( which has 146 neutrons and accounts for over 99 % ) and uranium - 235 ( which has 143 neutrons ) . Uranium has the highest atomic weight of the primordially occurring elements . Its density is about 70 % higher than that of lead , and slightly lower than that of gold or tungsten . It occurs naturally in low concentrations of a few parts per million in soil , rock and water , and is commercially extracted from uranium - bearing minerals such as uraninite . </P>
where is uranium located on the periodic table
where is uranium located on the periodic table
atomic number 92
atomic number 92