premise: Uranium has 92 neutrons.
hypothesis: Uranium is a chemical element with symbol U and atomic number 92 . A uranium atom has 92 protons and 92 electrons , of which 6 are valence electrons . 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 ) .