This checkpoint tests Block E: nuclear reactions, from nuclear stability and the origin of the elements to radioactive decay, half-life, radioisotope uses, fission and fusion, and the benefits and risks of nuclear energy.
This checkpoint assesses your understanding of nuclear reactions: how nuclei are built and why some are unstable, how elements form, the maths of half-life, and how society weighs the uses and risks of nuclear technology.
Inside the nucleus: nucleons, isotopes, the strong nuclear force and nuclear stability.
The Big Bang and how stars and supernovae forge the elements.
Radioactive decay: writing and balancing alpha and beta nuclear equations.
Half-life, decay curves and half-life calculations.
Using radioisotopes in medicine, industry and the environment.
Nuclear fission and fusion, chain reactions and mass-energy.
Nuclear energy: weighing benefits, risks and environmental impacts.
1. What holds protons and neutrons together in the nucleus, despite the electrostatic repulsion between the positively charged protons?
2. Two atoms are isotopes of the same element. This means they have the:
3. Which two elements were formed in the greatest amounts in the first few minutes after the Big Bang?
4. Where are most elements heavier than iron formed?
5. When a nucleus undergoes alpha decay, how do its mass number and atomic number change?
6. In the nuclear equation 22688Ra → 22286Rn + X, what is particle X?
7. A radioisotope has a half-life of 6 days. What fraction of the original sample remains after 18 days?
8. What does the half-life of a radioisotope measure?
9. Which statement correctly distinguishes nuclear fission from nuclear fusion?
10. Which statement gives the most balanced, evidence-based comparison of nuclear power and coal-fired power?
11. Explain what makes a nucleus unstable, then describe the particle emitted in alpha decay and the particle emitted in beta decay. 4 MARKS
12. Iodine-131 has a half-life of 8 days. A hospital starts with 80 g of iodine-131. Calculate how much remains after 24 days, showing your working, and explain why a short half-life is useful for a medical tracer. 4 MARKS
13. Discuss one beneficial use of radioisotopes and one risk of nuclear technology. Use specific evidence to support a balanced conclusion about whether the benefits outweigh the risks. 4 MARKS
Tick when you have finished all questions and reviewed your answers.