The table below gives details about some radioactive substances.
| Substance | Symbol | Type of radiation emitted | Half-life |
|---|---|---|---|
| sodium-24 | 1124Na^{24}_{11}\text{Na}1124Na | beta (β\betaβ) | 15 hours |
| radon-222 | 86222Rn^{222}_{86}\text{Rn}86222Rn | alpha (α\alphaα) | 3.8 days |
| xenon-133 | 54133Xe^{133}_{54}\text{Xe}54133Xe | beta (β\betaβ) | 5.2 days |
| krypton-81 | 3681Kr^{81}_{36}\text{Kr}3681Kr | gamma (γ\gammaγ) | 13 seconds |
Which of these substances has the greatest number of nucleons (protons and neutrons) in the nucleus of its atoms?
Which of these substances has the least number of electrons in the orbits of a neutral atom?
Which of these substances emit particles during radioactive decay?
Samples of each of these substances are decaying. Each sample starts with the same number of atoms. Which sample decays the most in one minute?
In a medical lung-ventilation test, a patient inhales a radioactive gas. The radiation needs to be highly penetrating to be detected outside the body, and the substance must decay very quickly to minimize the radiation dose to the patient. Which of these substances is most suitable?
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.