## Chemistry: A Molecular Approach (3rd Edition)

92 protons, 143 neutrons. Symbol is $^{235}_{92}U$
Mass number of Uranium-235 isotope = 235 Atomic number of Uranium = 92 = number of protons Number of neutrons = Mass number - Atomic number = 235 - 92 = 143 Isotopic symbol = $^{235}_{92}U$