The unstable nucleus of an isotope undergoes radioactive decay. During this process, the nucleon number (mass number) of the nucleus decreases by 4 and its proton number (atomic number) decreases by 2.
Which description of this radioactive decay event is correct?
The nucleus emits an α\alphaα-particle.
The nucleus emits a β−\beta^-β−-particle.
The nucleus emits γ\gammaγ-radiation.
The nucleus emits a positron (β+\beta^+β+-particle).
120 exam-style questions on CIE IGCSE Physics 5.2.3a Radioactive decay. Each one has a worked solution and a mark scheme showing where the marks go.