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Question bank›OCR A‑Level Chemistry A›2.1.1.1 Isotopes and sub-atomic particles

Isotopes and sub-atomic particles: OCR A‑Level Chemistry A questions

OCR A-Level Chemistry A past-paper questions on 2.1.1.1 Isotopes and sub-atomic particles, 2016–2025, with mark schemes and examiner’s reports where available.

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Paper 1 · Periodic Table, Elements and Physical ChemistryPaper 2 · Synthesis and Analytical TechniquesPaper 3 · Unified ChemistryAS Paper 1 · Breadth in ChemistryAS Paper 2 · Depth in Chemistry

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June 2025June 2024June 2023June 2022November 2021November 2020June 2019June 2018June 2017June 2016

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Q1
June 2025 · Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q1(a)(i)
June 2025 · Paper 3
2 marks2.1.1.1 Isotopes and sub-atomic particles
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Q21(a)
June 2025 · AS Paper 1
2 marks2.1.1.1 Isotopes and sub-atomic particles
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Q2
June 2024 · AS Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q1(a)(iii)
June 2023 · AS Paper 2
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q22(b)
June 2022 · AS Paper 1
2 marks2.1.1.1 Isotopes and sub-atomic particles 2.2.1.2 Filling orbitals and electron configurations
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Q21(b)
November 2021 · AS Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q21(b)
November 2020 · AS Paper 1
2 marks2.1.1.1 Isotopes and sub-atomic particles
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Q1(b)
June 2019 · Paper 3
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q21(a)
June 2019 · AS Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q21(b)
June 2019 · AS Paper 1
2 marks2.1.1.1 Isotopes and sub-atomic particles
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Q21(a)(i)
June 2018 · AS Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q1
June 2017 · Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q1
June 2017 · AS Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q22(a)(i)
June 2017 · AS Paper 1
2 marks2.1.1.1 Isotopes and sub-atomic particles 2.1.1.2 Relative masses and mass spectra
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Q1
June 2016 · AS Paper 1
1 mark2.1.1.1 Isotopes and sub-atomic particles
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Q21(a)
June 2016 · AS Paper 1
2 marks2.1.1.1 Isotopes and sub-atomic particles
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All 17 questions on Isotopes and sub-atomic particles, as a list

June 2025, Paper 1, Q1 (1 mark): The table shows the number of protons and neutrons in four different atoms. Atom Number of protons Number of neutrons W 17 18 X 18 18 Y 19 18 Z 18 19 Which two
June 2025, Paper 3, Q1(a)(i) (2 marks): Complete the table to show the number of protons, neutrons and electrons in the particles that cause the peaks at m/z 79 and 81. Number of Number of Number of m
June 2025, AS Paper 1, Q21(a) (2 marks): This part of the question is about sulfur. Complete the table below. Species Protons Neutrons Electrons 34S 16 16 18 [2]
June 2024, AS Paper 1, Q2 (1 mark): Which row shows the atomic structure of 25Mg2+? 2 Protons Neutrons Electrons A 10 12 13 B 10 15 12 C 12 13 10 D 12 13 14 Your answer [1]
June 2023, AS Paper 2, Q1(a)(iii) (1 mark): Complete the table to show the number of protons, neutrons and electrons in a 48Ti2+ ion. Protons Neutrons Electrons 48Ti2+ ion [1]
June 2022, AS Paper 1, Q22(b) (2 marks): Complete the table for an atom and an ion of two different elements. Mass Element Protons Neutrons Electron configuration Charge number 28 34 0 1s22s22p63s23p6
November 2021, AS Paper 1, Q21(b) (1 mark): Selenium, Se, has the atomic number 34. 76Se and 82Se are two isotopes of selenium. Complete the table to show the numbers of protons, neutrons and electrons in
November 2020, AS Paper 1, Q21(b) (2 marks): Most elements contain atoms of different isotopes. State any differences and similarities between the atomic structures of isotopes of the same element. Differe
June 2019, Paper 3, Q1(b) (1 mark): Explain why a small proportion of molecules in water have a relative molecular mass of 20. [1]
June 2019, AS Paper 1, Q21(a) (1 mark): Most elements contain different isotopes. State two differences between isotopes of the same element. [1]
June 2019, AS Paper 1, Q21(b) (2 marks): Complete the table for an atom and an ion of two different elements. Mass Element Protons Neutrons Electrons Charge number 26 28 0 80 36 2− [2]
June 2018, AS Paper 1, Q21(a)(i) (1 mark): Complete the table to show the atomic structure of 30Si. Protons Neutrons Electrons 30Si [1]
June 2017, Paper 1, Q1 (1 mark): Which atom is not an isotope of iodine? Number of neutrons Mass number A 72 125 B 74 127 C 75 128 D 77 129 Your answer [1]
June 2017, AS Paper 1, Q1 (1 mark): Which ion has a different number of electrons from the other three ions? Ga3+ A Cl − B S2− C Ca2+ D Your answer [1]
June 2017, AS Paper 1, Q22(a)(i) (2 marks): The species causing the peaks in the mass spectrum are 1+ ions of magnesium. Complete the table to show the number of protons, neutrons and electrons in each 1+
June 2016, AS Paper 1, Q1 (1 mark): Which row shows the atomic structure of 37Cl–? 1 protons neutrons electrons A 17 18 20 B 17 20 18 C 18 19 17 D 20 17 21 Your answer [1]
June 2016, AS Paper 1, Q21(a) (2 marks): Copper and nickel each exist as a mixture of isotopes. State the similarities and differences between the atomic structure of isotopes of the same element. Simi

Nearby topics:2.1.1.2 Relative masses and mass spectra The whole bank

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