Four statements about two different isotopes of the same element are listed. Which statement must be correct?
They have different numbers of protons.
They have different chemical properties.
They have different numbers of neutrons.
They have different numbers of electrons in their neutral atoms.
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.