The nucleus of a radium atom contains 138 neutrons and 88 protons. It decays by emitting an α\alphaα-particle. How many neutrons and how many protons remain in the nucleus after this decay?
134 neutrons, 86 protons
136 neutrons, 88 protons
136 neutrons, 86 protons
138 neutrons, 88 protons
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.