plumiIsotopes, mass spectra and relative atomic mass: Edexcel International A Level Chemistry questions
Edexcel International A Level Chemistry past-paper questions on 2.1.2 Isotopes, mass spectra and relative atomic mass, 2019–2025, with mark schemes and examiner’s reports where available.
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All 43 questions on Isotopes, mass spectra and relative atomic mass, as a list
- June 2025, AS Unit 1, Q6 (1 mark): Which is the correct order for the processes in a mass spectrometer? A deflection detection ionisation vaporisation B vaporisation ionisation deflection detecti
- January 2025, AS Unit 1, Q23(a)(i) (3 marks): Calculate the mass number of the fifth isotope of germanium. The relative atomic mass of germanium is 72.6. You must show your working. (3)
- January 2025, AS Unit 1, Q23(a)(ii) (1 mark): Give the main reason why the answer in (a)(i) should not be quoted to more than 2 significant figures. (1)
- June 2024, AS Unit 1, Q16(a)(ii) (2 marks): Calculate the relative atomic mass of a sample of silicon, using the isotopic abundance data provided. Give your answer to 3 significant figures. Isotope Abunda
- June 2024, AS Unit 1, Q16(a)(iii) (1 mark): In the mass spectrum of silicon, there is also a small peak at m / z = 14. Deduce the formula of this particle. (1)
- June 2024, AS Unit 2, Q13 (1 mark): Bromine and chlorine each have two stable isotopes, 79Br, 81Br, 35Cl and 37Cl. Which statement is true? A the atomic radius of 81Br is greater than that of 79Br
- January 2024, AS Unit 1, Q20(a)(i) (4 marks): Calculate the relative abundance and hence the mass number of the third isotope. Give your answer to the appropriate number of significant figures. You must sho
- January 2024, AS Unit 1, Q20(a)(ii) (1 mark): State one similarity and one difference between these isotopes. (1)
- January 2024, AS Unit 1, Q20(a)(iii) (1 mark): State which of these isotopes would be deflected most in a mass spectrometer. Justify your answer. (1)
- October 2023, AS Unit 1, Q8 (1 mark): In which region of a mass spectrometer are particles ionised? P Q + R recorder amplifier S A region P B region Q C region R D region S
- January 2023, AS Unit 1, Q7 (1 mark): The mass spectrum of an element is shown. 70 60 50 40 Percentage abundance 30 20 10 0 89 90 91 92 93 94 95 96 97 m / z What is the relative atomic mass of this
- October 2022, AS Unit 1, Q10(a) (1 mark): In which region of this mass spectrometer are the ions accelerated? (1) P Q electromagnet vaporised to vacuum sample pump R S amplifier chart recorder A region
- October 2022, AS Unit 1, Q10(b) (1 mark): Four iron ions are present in a stream of ions in a mass spectrometer. The paths of these ions are shown. path 4 stream of ions path 3 path 1 path 2 Which of th
- October 2022, AS Unit 1, Q16(a) (2 marks): Naturally‑occurring germanium consists of five stable isotopes. Explain what is meant by the term isotopes. (2)
- October 2022, AS Unit 1, Q16(b) (2 marks): The mass spectrum of a sample of germanium is shown. 40 36.7 30 27.4 Percentage 20.6 20 abundance 10 7.7 7.6 0 70 71 72 73 74 75 76 77 m / z Calculate the relat
- June 2022, AS Unit 1, Q6(b) (1 mark): In a mass spectrometer, scandium forms Sc+ and Sc2+ ions. What is the m / z value for the mass spectrum peak due to the Sc2+ ions? (1) A 22.5 B 33.0 C 45.0 D 90
- June 2022, AS Unit 1, Q20(a) (1 mark): State what is meant by the term isotopes. (1)
- June 2022, AS Unit 1, Q20(c)(ii) (2 marks): Describe the formation of the molecular ion of bromine in the mass spectrometer. Include an equation. State symbols are not required. (2)
- June 2022, AS Unit 1, Q20(d) (3 marks): The percentage abundances of the isotopes in a different sample of bromine are shown. Isotope Percentage abundance bromine‑79 56.38 % bromine‑81 43.62 % Calcula
- January 2022, AS Unit 1, Q20(b)(ii) (2 marks): Explain the term isotopes, using the information in the table. (2)
- January 2022, AS Unit 1, Q20(b)(iii) (1 mark): State why the two isotopes of copper have the same chemical reactions. (1)
- January 2022, AS Unit 1, Q20(b)(iv) (2 marks): The relative atomic mass of copper in this sample is 63.4. Calculate the percentage abundances of the isotopes 63Cu and 65Cu in this sample. You must show your
- October 2021, AS Unit 1, Q3(a) (1 mark): Which process occurs in region R? (1) A the sample is vaporised using a heater B electrons are removed from molecules or atoms and positive ions are formed C el
- October 2021, AS Unit 1, Q3(b) (1 mark): Which statement is correct for region T? (1) A ions with a greater mass have a smaller deflection B ions with a greater mass have a greater deflection C ions wi
- October 2021, AS Unit 1, Q13(a)(i) (2 marks): Data obtained using the mass spectrum of silicon are shown. Isotope mass number Relative abundance 28 92.17 29 4.71 30 3.12 Calculate the relative atomic mass o
- October 2021, AS Unit 1, Q13(a)(ii) (1 mark): Suggest a reason why there is a small peak in the mass spectrum of silicon at m / z = 14 (1)
- June 2021, AS Unit 1, Q3 (1 mark): The mass spectrum of a sample of an element has only two peaks. 80 70 60 50 Relative 40 abundance 30 20 10 0 190 191 192 193 194 m / z What is the approximate r
- June 2021, AS Unit 1, Q24(b) (2 marks): A sample of iron contains the following isotopes. Isotope Percentage abundance 54Fe 5.84 56Fe 91.68 57Fe 2.17 58Fe 0.31 Calculate the relative atomic mass of th
- June 2021, AS Unit 2, Q22(c)(i) (2 marks): Give the reason for the ratio of peak heights at m / z values of 102, 100 and 98. (2)
- June 2021, AS Unit 2, Q22(c)(ii) (1 mark): Suggest an identity for the peak at m / z = 63. (1)
- June 2021, AS Unit 2, Q22(c)(iii) (1 mark): The peak at m / z = 65 has been omitted. Draw on the mass spectrum the peak at m / z = 65, showing its relative intensity. (1)
- January 2021, AS Unit 1, Q18(d)(i) (2 marks): State what is meant by the term isotopes, in terms of subatomic particles. (2)
- January 2021, AS Unit 1, Q18(d)(ii) (2 marks): Calculate the relative atomic mass of sulfur in this sample. Give your answer to two decimal places. (2)
- January 2021, AS Unit 1, Q18(e)(i) (1 mark): Calculate the number of sulfur atoms in the molecular ion. You must show your working. (1)
- January 2021, AS Unit 1, Q18(e)(ii) (2 marks): Suggest the formula of the most stable ion shown by this spectrum. (2)
- October 2020, AS Unit 1, Q6(a) (1 mark): What is the Ar of the element? (1) A 42.0 B 48.0 C 63.6 D 64.0
- October 2020, AS Unit 1, Q6(b) (1 mark): Which species could be responsible for the peak at m / z = 32.5? (1) A 32S+ B 63Cu2+ C 65Cu2+ D 98Tc3+
- January 2020, AS Unit 1, Q2 (1 mark): A sample of an element X contains only the isotopes shown. Isotope Percentage abundance 58X 68.077 60X 26.223 61X 1.140 62X 3.634 64X 0.926 What is the relative
- January 2020, AS Unit 1, Q18(f)(ii) (2 marks): Suggest why there could be a small peak at m / z = 36 in the mass spectrum of chlorine gas. (2)
- June 2019, AS Unit 1, Q10 (1 mark): Isotopes are atoms of an element that have different A electronic structures B numbers of electrons C numbers of protons D numbers of neutrons
- June 2019, AS Unit 1, Q12 (1 mark): The mass spectrum of a sample of silicon is shown. Relative abundance 28 29 30 m / z What is the best estimate for the relative atomic mass of silicon in this s
- January 2019, AS Unit 1, Q2 (1 mark): A sample of silicon contains the following isotopes. Isotope Percentage abundance 28Si 81.21 29Si 14.10 30Si 4.69 What is the relative atomic mass of silicon, t
- January 2019, AS Unit 1, Q24(c)(i) (2 marks): A sample of nitrogen trichloride contained only nitrogen atoms with mass number 14, and chlorine atoms with mass numbers 35 and 37. Give the formula and mass/ch
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