A thorium nucleus 90230Th^{230}_{90}\text{Th}90230Th decays to form radium by emitting an α\alphaα-particle. Radium decays to actinium by emitting a β\betaβ-particle.
Which option gives the atomic number and mass number of this isotope of actinium?
Atomic number: 89, Mass number: 226
Atomic number: 88, Mass number: 226
Atomic number: 89, Mass number: 230
Atomic number: 87, Mass number: 226
484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.