An isotope of cesium is radioactive. It decays by emitting a β−\beta^-β−-particle.
What happens to the nucleus of a cesium atom during the emission of the β−\beta^-β−-particle?
It becomes the nucleus of a different isotope of cesium with fewer neutrons.
It becomes the nucleus of a different isotope of cesium with more neutrons.
It becomes the nucleus of an element with a higher proton number.
It becomes the nucleus of an element with a lower proton number.
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.