Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Radioactivity and Particles
123 practice questions
Topics covered
Practice questions
21–30 of 59 · Normal
Question 21
3 marks · Normal
Answer and see the solution →A student claims that all isotopes of hydrogen are equally stable. Use your knowledge of isotopes and nuclear forces to explain why this statement is not correct.
Question 22
3 marks · Normal
Answer and see the solution →Explain why heavy elements like uranium have more neutrons than protons in their most stable isotope.
Question 23
4 marks · Normal
Answer and see the solution →The table below gives information about three isotopes of lithium.
Properties of lithium isotopes Isotope Protons Neutrons Lithium-6 3 3 Lithium-7 3 4 Lithium-8 3 5 (a)[1 mark]State, for all isotopes of lithium, what determines that they are all lithium atoms.
(b)[3 marks]Explain what effect increasing the number of neutrons has on the stability of the lithium nucleus. Use examples from the table.
Question 24
3 marks · Normal
Answer and see the solution →A student investigates two isotopes of boron: boron-10 and boron-12. Boron-10 is stable, but boron-12 decays quickly after it is produced.
Explain, in terms of neutrons and protons, why boron-12 is less stable than boron-10.
Question 25
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 26
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 27
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 28
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 29
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?
Question 30
5 marks · Normal
Answer and see the solution →A radioactive isotope of nitrogen, , decays by beta minus emission. A scientist is studying nuclear stability and writes an equation for this decay.
(a)[2 marks]Write the balanced nuclear equation for the beta minus decay of .
(b)[2 marks]State, with reasons, how the numbers of protons and neutrons change in the nucleus as a result of this decay.
(c)[1 mark]Explain why some isotopes with the same number of protons as are stable, while others are unstable.