Isotopes: past paper questions
Real questions on isotopes
The newest 20 of 62 written questions. Open one to see it on the real paper.
- 0620/41 · May/June 2026 · Q2b(i)[2]
Explain, in terms of protons and neutrons, the similarity and difference between isotopes of the same element.
See it on the paper → - 0620/43 · May/June 2026 · Q2b(i)[2]
State the meaning of the term isotopes.
See it on the paper → - 0620/43 · May/June 2026 · Q2b(ii)[1]
The isotopes of boron have mass numbers of 10 and 11. The relative atomic mass of boron is 10.8. Calculate the percentage abundance of the isotope of boron with a mass number of 10. percentage abundance =
See it on the paper → - 0620/32 · February/March 2026 · Q7a(i)[2]
State the meaning of the term isotopes.
See it on the paper → - 0620/32 · February/March 2026 · Q7a(ii)[1]
Relative atomic mass is the average mass of an atom of an element compared to the mass of a specific isotope. Identify the specific isotope used for this comparison. Draw a circle around your chosen answer. 12 C 14 C 16 O 18 O
See it on the paper → - 0620/42 · February/March 2026 · Q2d(ii)[2]
A sample of indium contains two isotopes, 113 In and 115 In. Complete Table 2.1 to show the number of protons and the number of neutrons in one atom of each isotope of indium. Table 2.1 isotope 115 In number of neutrons 113 In number of protons
See it on the paper → - 0620/42 · February/March 2026 · Q2d(iii)[2]
Table 2.2 shows the relative abundances of the two isotopes in the sample of indium. Table 2.2 isotope relative abundance 113 In 115 In 1 19 Calculate the relative atomic mass of this sample of indium to one decimal place. (iii) relative atomic mass =
See it on the paper → - 0620/41 · October/November 2025 · Q1b(i)[2]
Define the term isotopes. (i)
See it on the paper → - 0620/41 · October/November 2025 · Q1b(ii)[1]
Explain why all isotopes of the same element have the same chemical properties.
See it on the paper → - 0620/42 · October/November 2025 · Q2b[2]
Table 2.1 shows four different isotopes of iron, A, B, C and D. B C D 54 Fe 56 Fe 57 Fe 58 Fe Explain why A, B, C and D are isotopes of iron. A Table 2.1
See it on the paper → - 0620/43 · October/November 2025 · Q1c(i)[1]
The relative atomic mass, A r , of an element is the average mass of its isotopes compared to one atom of isotope X. Identify isotope X.
See it on the paper → - 0620/43 · October/November 2025 · Q1c(ii)[1]
A sample of magnesium consists of two isotopes with mass numbers 24 and 26. [A r : Mg, 24.3] Calculate the percentage abundance of the isotope of magnesium with mass number 24. percentage abundance =
See it on the paper → - 0620/31 · May/June 2025 · Q3a(ii)[3]
S 1 6 3 6 S 1 6 Fig. 3.1 Complete Table 3.1 to show the number of protons, neutrons and electrons in one atom of these isotopes. Table 3.1 protons neutrons electrons 3 3 S 1 6 3 6 S 1 6 Two isotopes of sulfur are shown in Fig. 3.1. (ii)
See it on the paper → - 0620/32 · May/June 2025 · Q3a(ii)[3]
Two isotopes of phosphorus are shown in Fig. 3.1. 32 15 P Fig. 3.1 Complete Table 3.1 to show the number of protons, neutrons and electrons in one atom of these isotopes. Table 3.1 neutrons electrons 31 15 P 32 15 P protons 31 15 P (ii)
See it on the paper → - 0620/33 · May/June 2025 · Q4a(ii)[3]
Two isotopes of nitrogen are shown in Fig. 4.1. 14 N 7 15 N 7 Fig. 4.1 Complete Table 4.1 to show the number of protons, neutrons and electrons in one atom of these isotopes. Table 4.1 protons neutrons electrons 14 N 7 15 N 7 (ii)
See it on the paper → - 0620/41 · May/June 2025 · Q2b(i)[3]
Complete Table 2.2 to show the number of electrons, neutrons and protons in one atom or ion of these isotopes. Table 2.2 isotope electrons neutrons protons 39 19 K 41 + 19 K
See it on the paper → - 0620/41 · May/June 2025 · Q2b(ii)[2]
Table 2.3 shows the relative masses and the percentage abundances of the two isotopes in a sample of potassium. Table 2.3 relative mass of isotope percentage abundance of isotope 39 90 41 10 Calculate the relative atomic mass of this sample of potassium to one decimal place. (ii)
See it on the paper → - 0620/41 · May/June 2025 · Q2b(iii)[1]
An isotope of aluminium has a nucleon number of 27. Aluminium has a relative atomic mass of 27. State what conclusion can be made from this information.
See it on the paper → - 0620/42 · May/June 2025 · Q5d(i)[1]
State the term given to these naturally occurring atoms of rubidium.
See it on the paper → - 0620/42 · May/June 2025 · Q5d(ii)[3]
Complete Table 5.1 to show the number of protons, neutrons and electrons in the atom and ion of rubidium shown. Table 5.1 85 Rb 87 Rb + protons neutrons electrons
See it on the paper →
What examiners said
Comprehensive responses • Most candidates were able to state the correct definition of isotopes using protons and neutrons. Limited responses • Some candidates confused the particles and got them the other way around. For example, same number of neutrons and different number of protons.
— Examiner report, February/March 2026, 0620/32 Q7(a)(i) (Cambridge)
Comprehensive responses • A few candidates could recognise the specific isotope. Limited responses • Many candidates confused recognising the correct isotope. Candidates used all the other responses and sometimes they circled two responses.
— Examiner report, February/March 2026, 0620/32 Q7(a)(ii) (Cambridge)
Comprehensive responses • Most candidates correctly filled in Table 2.1. Limited responses • Some candidates confused the number of neutrons with the mass number.
— Examiner report, February/March 2026, 0620/42 Q2(d)(ii) (Cambridge)
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