Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
THE STABILITY OF ISOTOPES
20 practice questions
Practice questions
1–3 of 3 · 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.