An atomic nucleus decays by one or more radioactive decay processes.
What causes the proton number to decrease by 3?
Two α\alphaα-decays followed by one β\betaβ-decay
One α\alphaα-decay only
Two α\alphaα-decays followed by two β\betaβ-decays
One α\alphaα-decay followed by one β\betaβ-decay
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.