Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Radioactivity and Particles
123 practice questions
Topics covered
Practice questions
51–60 of 123
Question 51
1 mark · Normal
Answer and check →Which situation is most likely to make a nucleus unstable?
- A.Too few neutrons relative to protons
- B.More protons than neutrons
- C.A balanced number of neutrons and protons
- D.No protons in the nucleus
Question 52
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 53
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 54
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 55
4 marks · Easy
Answer and see the solution →A neutral atom of oxygen has 8 protons, 8 neutrons, and 8 electrons.
(a)[1 mark]Write down the symbol for this oxygen nucleus using atomic notation.
(b)[1 mark]Give the definition of the term 'mass number'.
(c)[2 marks]Explain how this atom would change if it became an isotope called oxygen-17.
Question 56
4 marks · Easy
Answer and see the solution →The diagram below shows two isotopes of carbon:
Carbon-12 and Carbon-14 nuclei (schematic) (a)[1 mark]State what is meant by the term "isotope".
(b)[2 marks]Explain how the number of neutrons affects the stability of these two isotopes of carbon.
(c)[1 mark]Give one possible use of a radioactive isotope of carbon.
Question 57
4 marks · Normal
Answer and see the solution →Radon-222 is a radioactive gas found in some rocks. It decays by emitting an alpha particle.
(a)[1 mark]Complete the nuclear equation for this alpha decay:
(b)[1 mark]How do the atomic number and mass number of the daughter nucleus compare to those of the radon nucleus after the alpha emission?
(c)[1 mark]Radon-222 is an isotope of radon. State what is meant by the term isotope.
(d)[1 mark]Explain, in terms of neutrons and protons, why some isotopes, like radon-222, are radioactive.
Question 58
4 marks · Normal
Answer and see the solution →Potassium-40 is an unstable isotope present in the human body. Its nucleus can decay by emitting a beta minus particle, turning into calcium-40.
(a)[2 marks]Write a balanced nuclear equation for this beta minus decay. Supply all atomic numbers and mass numbers.
(b)[1 mark]Describe the changes in the atomic number and mass number that occur in the nucleus during this decay.
(c)[1 mark]Explain why potassium-40 is unstable in terms of neutrons and nuclear stability.
Question 59
5 marks · Normal
Answer and see the solution →An isotope of sodium, , is unstable and decays by emitting a beta minus () particle.
(a)[2 marks]Write the balanced nuclear equation for this decay, including the correct atomic and mass numbers for the product nucleus and the beta particle.
(b)[1 mark]Explain what happens to the atomic number and mass number of the nucleus during beta minus decay.
(c)[2 marks]Is the product nucleus more stable after the decay? With reference to neutrons and protons, explain your answer briefly.
Question 60
6 marks · Normal
Answer and see the solution →A radioactive source emits both alpha and gamma radiation. The source is tested in a lab using a Geiger-Muller (GM) tube, as shown below.
(a)[2 marks]Describe how the GM tube is used to detect ionising radiation. Name one other way, apart from a GM tube, that ionising radiation can be detected.
(b)[2 marks]A student places a thin sheet of paper between the source and the GM tube, and records the count rate. She then places a thick lead block instead and records the count rate again. Explain what you would expect to happen to the count rate in both cases, and what this shows about the properties of alpha and gamma radiation.
(c)[2 marks]Alpha particles are helium nuclei. State the number of protons and neutrons in an alpha particle. How does the emission of an alpha particle affect the atomic number and mass number of a nucleus?