0654.C2.2.03 — Define proton number / atomic number as the number of protons in the nucleus of an atom: past paper questions

Real questions on 0654.c2.2.03 — define proton number / atomic number as the number of protons in the nucleus of an atom

The newest 11 of 11 written questions. Open one to see it on the real paper.

1. 0654/32 · February/March 2026 · Q6c(ii)[1]

   Deduce the number of electrons in this atom of copper.

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2. 0654/42 · October/November 2025 · Q12a(i)[1]

   Determine the number of protons in the nucleus of this atom.

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3. 0654/32 · May/June 2025 · Q7a(i)[1]

   State what the number 29 represents.

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4. 0654/42 · May/June 2025 · Q5c[1]

   State the number of atoms in 1 mole of carbon. number of atoms =

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5. 0654/32 · February/March 2024 · Q11c(ii)[1]

   Deduce the number of electrons in this atom of zinc. number of electrons =

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6. 0654/33 · May/June 2023 · Q11a(i)[1]

   An atom of calcium has 20 protons and 20 neutrons. State the number of electrons in this calcium atom.

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7. 0654/33 · May/June 2022 · Q8a(iv)[1]

   State the number of electrons in an iodine atom.

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8. 0654/32 · February/March 2022 · Q5a(iii)[1]

   Another atom of iron has a nucleon number of 54. State the proton number of this atom of iron. proton number =

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9. 0654/33 · October/November 2021 · Q8a(i)[1]

   State the number of electrons in one atom of iron-54.

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10. 0654/21 · May/June 2021 · Q40[1]

    What happens to the proton number (atomic number) of the nucleus?

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11. 0654/33 · May/June 2019 · Q2a(i)[1]

    Explain what the numbers 19 to 36 represent for the elements in Period 4 from K to Kr.

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What examiners said

Comprehensive responses • Many candidates were able to use the proton number to determine the number of electrons in the atom. Limited responses • Some candidates determined the number of neutrons in the atom.

— Examiner report, February/March 2026, 0654/32 Q6(c)(ii) (Cambridge)

Many candidates thought 29 represented the number of electrons or the mass number of the atom, although a large proportion did know it was the proton number. Candidates are encouraged to be specific in their use of language and state in full that the ‘number of protons’ is represented by this number not just ‘protons’.

— Examiner report, May/June 2025, 0654/32 Q7(a)(i) (Cambridge)

Few candidates were able to state the number of atoms in 1 mole. Candidates that did attempt this often gave an inaccurate value.

— Examiner report, May/June 2025, 0654/42 Q5(c) (Cambridge)