Thorium-232 is a radioactive isotope. It undergoes a chain of decays and eventually forms the stable isotope lead-208. These two isotopes are represented as shown below:
90232Th82208Pb ^{232}_{90}\text{Th} \qquad ^{208}_{82}\text{Pb} 90232Th82208PbDuring this chain of decay, how many protons and how many neutrons are lost from a single nucleus of thorium-232 to form a single nucleus of lead-208?
8 protons, 16 neutrons
8 protons, 24 neutrons
16 protons, 8 neutrons
24 protons, 8 neutrons
170 exam-style questions on CIE IGCSE Physics 5.1.2a Composition of the nucleus and isotopes. Each one has a worked solution and a mark scheme showing where the marks go.