One nuclide of carbon has 121212 nucleons and the other nuclide of carbon has 141414 nucleons. The proton number of carbon is 666.
How many protons are there in a neutral atom of carbon-12?
How many neutrons are there in a neutral atom of carbon-14?
How many electrons are there in a neutral atom of carbon-14?
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.