Ionisation energy: past paper questions
Real questions on ionisation energy
The newest 20 of 62 written questions. Open one to see it on the real paper.
- 9701/21 · May/June 2025 · Q2d[1]
Write an equation to represent the first ionisation energy of iron.
See it on the paper → - 9701/21 · May/June 2025 · Q2e[4]
Suggest how the value for the first ionisation energy of 54 Fe compares to the first ionisation energy of 56 Fe. Explain your answer in terms of the factors that affect ionisation energy.
See it on the paper → - 9701/23 · May/June 2025 · Q1b(i)[1]
Write an equation to represent the first ionisation energy of sulfur.
See it on the paper → - 9701/23 · May/June 2025 · Q1b(ii)[2]
Explain why the first ionisation energy of sulfur is less than the first ionisation energy of phosphorus.
See it on the paper → - 9701/22 · February/March 2025 · Q2b(ii)[2]
Table 2.1 shows successive ionisation energy values for beryllium, Be. Table 2.1 ionisation energy / kJ mol –1 1st 2nd 3rd 4th 900 1760 14 800 21 000 Use Table 2.1 to state and explain: • • the general trend in these values the significance of the large difference between the 2nd and 3rd ionisation energies.
See it on the paper → - 9701/21 · October/November 2024 · Q3c(i)[1]
1-mark question — its maths and diagrams are best seen on the paper.
See it on the paper → - 9701/21 · October/November 2024 · Q3c(ii)[1]
Construct an equation to represent the second ionisation energy of Si.
See it on the paper → - 9701/22 · October/November 2024 · Q3c(i)[1]
Construct an equation to represent the third ionisation energy of P.
See it on the paper → - 9701/22 · October/November 2024 · Q3c(ii)[1]
1-mark question — its maths and diagrams are best seen on the paper.
See it on the paper → - 9701/23 · October/November 2024 · Q3c(i)[1]
1-mark question — its maths and diagrams are best seen on the paper.
See it on the paper → - 9701/23 · October/November 2024 · Q3c(ii)[1]
Construct an equation to represent the second ionisation energy of Si.
See it on the paper → - 9701/21 · October/November 2023 · Q1a(ii)[1]
Construct an equation to represent the first ionisation energy of P.
See it on the paper → - 9701/21 · October/November 2023 · Q1a(iii)[1]
Three possible values for the first ionisation energy of S are given. 1000 kJ mol –1 1160 kJ mol –1 1320 kJ mol –1 Circle the correct value. Explain your choice by comparing your chosen value to those of P and Cl .
See it on the paper → - 9701/22 · October/November 2023 · Q1b(ii)[1]
Construct an equation to represent the first ionisation energy of Si.
See it on the paper → - 9701/22 · October/November 2023 · Q1b(iii)[1]
Three possible values for the first ionisation energy of P are given. 619 kJ mol –1 893 kJ mol –1 1060 kJ mol –1 Circle the correct value. Explain your choice, including a comparison of your chosen value to those of Si and S.
See it on the paper → - 9701/22 · October/November 2023 · Q3b(iii)[1]
Explain why reaction 1 is a disproportionation reaction. Explain your reasoning with reference to relevant oxidation numbers.
See it on the paper → - 9701/23 · October/November 2023 · Q1a(ii)[1]
Construct an equation to represent the first ionisation energy of P.
See it on the paper → - 9701/23 · October/November 2023 · Q1a(iii)[1]
Three possible values for the first ionisation energy of S are given. 1000 kJ mol –1 1160 kJ mol –1 1320 kJ mol –1 Circle the correct value. Explain your choice by comparing your chosen value to those of P and Cl .
See it on the paper → - 9701/21 · May/June 2023 · Q1c[1]
Construct an equation to represent the first ionisation energy of Te.
See it on the paper → - 9701/21 · May/June 2023 · Q1d(i)[2]
The radius of Te ions decreases after each successive ionisation. State two factors that are responsible for the increase in the first six ionisation energies of Te.
See it on the paper →
What examiners said
The explanations given here were quite often too vague or incorrectly worded, such as talking about an increase in overall nuclear charge. In explaining the large difference between the 2nd and 3rd ionisation energies, comments regarding the third electron’s being removed from a shell closer to the nucleus were often absent.
— Examiner report, February/March 2025, 9701/22 Q2(b)(ii) (Cambridge)
The equation to represent the first ionisation of P was well answered. A common error was to omit the state symbols of (g) throughout. The question required candidates to choose one of three possible values, given in the question, to represent the first ionisation energy of S and to explain their choice. Most candidates did not mention that S has a pair of electrons in a 3p orbital, which experie...
— Examiner report, October/November 2023, 9701/21 Q1(a)(ii) (Cambridge)
Many equations showed appropriate species. State symbols, essential in any equation to represent the first ionisation energy process, were included less often.
— Examiner report, October/November 2023, 9701/22 Q1(b)(ii) (Cambridge)
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