Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Radioactivity
46 practice questions
Topics covered
Practice questions
31–40 of 46
Question 31
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 32
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 33
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 34
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 35
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 36
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 37
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 38
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 39
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 40
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.