Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Radioactivity
46 practice questions
Topics covered
Practice questions
1–5 of 5 · Hard
Question 1
4 marks · Hard
Answer and see the solution →The isotope oxygen-19 has 8 protons and 11 neutrons. Oxygen-16 is a stable isotope. Explain, using scientific reasoning, why oxygen-19 is less stable than oxygen-16.
Question 2
5 marks · Hard
Answer and see the solution →A nucleus of potassium-40 () decays by emitting a beta minus particle to form a stable isotope.
(a)[2 marks]Write a balanced nuclear equation for this decay, including the atomic and mass numbers of all particles.
(b)[3 marks]Explain, using your answer, what has changed inside the nucleus.
Question 3
5 marks · Hard
Answer and see the solution →Explain, in detail, why nuclei with either far too few or far too many neutrons compared to protons tend to be unstable. In your answer, refer to the balance of forces in the nucleus and the typical changes that such nuclei might undergo to become more stable.
Question 4
5 marks · Hard
Answer and see the solution →A sample contains the isotope chlorine-36, which decays by beta minus emission. After 72,000 years, a scientist finds that only 25% of the original chlorine-36 remains.
(a)[2 marks]Write a balanced nuclear equation for the beta minus decay of chlorine-36. State the names and atomic numbers of the products formed.
(b)[3 marks]Calculate the half-life of chlorine-36. Give your answer to the nearest thousand years.
Question 5
5 marks · Hard
Answer and see the solution →Two isotopes of cobalt are compared in an experiment. Both have atomic number 27, but cobalt-59 is stable, while cobalt-60 is unstable and undergoes beta minus decay.
(a)[2 marks]Explain how the numbers of neutrons affect the stability of cobalt-59 and cobalt-60.
(b)[3 marks]Cobalt-60 has a half-life of 5.3 years. What percentage of a sample will remain after 15.9 years? Show your working.