How many neutrons and how many protons are contained in a nucleus of 90232Th^{232}_{90}\text{Th}90232Th?
909090 neutrons, 142142142 protons
142142142 neutrons, 909090 protons
142142142 neutrons, 232232232 protons
232232232 neutrons, 909090 protons
284 exam-style questions on CIE IGCSE Physics 5.1 The nuclear model of the atom, covering 5.1.1a Structure of the atom and ions, 5.1.1b Alpha-particle scattering, 5.1.2a Composition of the nucleus and isotopes, 5.1.2b Proton number, nucleon number and nuclide notation, and 5.1.2c Nuclear fission and nuclear fusion. Each one has a worked solution and a mark scheme showing where the marks go.