Atomic structure: Edexcel International GCSE Chemistry questions

Every Edexcel International GCSE Chemistry exam question on Atomic structure (specification points 1.14–1.17), 2019–2025, with its mark scheme and examiner’s report.

All 94 questions on Atomic structure, as a list

June 2025, Paper 1, Q1(a) (3 marks): Label the three subatomic particles on the diagram. (3)
June 2025, Paper 1, Q1(b) (4 marks): Use information from the diagram to complete the table for this element. (4) mass number group number period number electronic configuration
June 2025, Paper 2, Q3(a)(i) (2 marks): State, in terms of subatomic particles, what is meant by the term isotopes. (2)
June 2025, Paper 2, Q3(a)(ii) (3 marks): Calculate the relative atomic mass (Ar) of magnesium. Give your answer to one decimal place. (3) Ar =
June 2025 (R), Paper 1, Q4(a) (3 marks): Table 1 shows some information about sub‑atomic particles. Complete Table 1 by giving the missing information. (3) Relative Relative mass charge Neutron 0 Proto
June 2025 (R), Paper 1, Q4(b)(i) (1 mark): Give the letter of the species that has 3 electrons in its outer shell. (1)
June 2025 (R), Paper 1, Q4(b)(ii) (1 mark): Give the letter of the species that is an ion with a 3− charge. (1)
June 2025 (R), Paper 1, Q4(b)(iii) (1 mark): Give the letter of the species with a mass number of 19 (1)
June 2025 (R), Paper 1, Q4(c) (2 marks): A sample of lithium contains two isotopes, 6Li and 7Li. In terms of sub‑atomic particles, give one similarity and one difference between these isotopes. (2) sim
June 2025 (R), Paper 1, Q4(d) (3 marks): A sample of magnesium contains 79.0% of 24Mg, 10.0% of 25Mg and 11.0% of 26Mg. Calculate the relative atomic mass, Ar , of this sample of magnesium. Give your a
November 2024, Paper 2, Q1(a)(i) (1 mark): Give the letter of the species that is a negative ion. (1)
November 2024, Paper 2, Q1(a)(ii) (1 mark): Give the letter of the species that has a full outer shell of electrons. (1)
November 2024, Paper 2, Q1(a)(iii) (1 mark): Give the letter of the species that has an atomic number equal to its mass number. (1)
November 2024, Paper 2, Q1(b) (2 marks): Explain why species B and C are atoms of the same element with identical chemical properties. (2)
November 2024, Paper 2, Q1(c) (2 marks): A proton has a mass of 1.6726 × 10–24 g. A neutron has a mass of 1.6740 × 10–24 g. Calculate the mass, in grams, of the nucleus of an atom of species C. (2) mas
June 2024, Paper 1, Q3(c) (4 marks): A sample of element Z contains three isotopes. The table shows the numbers of particles in the nucleus of each isotope and the percentage abundance of each isot
June 2024 (R), Paper 1, Q1(a)(i) (1 mark): Which species is an atom? (1)
June 2024 (R), Paper 1, Q1(a)(ii) (1 mark): Which species is an ion with a positive charge? (1)
June 2024 (R), Paper 1, Q1(a)(iii) (1 mark): Which species is an ion with a 3− charge? (1)
June 2024 (R), Paper 1, Q1(b)(i) (1 mark): State what is meant by the term atomic number. (1)
June 2024 (R), Paper 1, Q1(b)(ii) (1 mark): State what is meant by the term mass number. (1)
June 2024 (R), Paper 2, Q2(a)(i) (1 mark): What is the name of the particle labelled W? (1) A electron B ion C neutron D proton
June 2024 (R), Paper 2, Q2(a)(ii) (1 mark): What is the mass number of this atom? (1) A 4 B 5 C 9 D 13
June 2024 (R), Paper 2, Q2(b)(i) (2 marks): In terms of sub-atomic particles, give one similarity and one difference between the two isotopes. (2) similarity difference
June 2024 (R), Paper 2, Q2(b)(ii) (2 marks): A sample of lithium contains 7.5% of 6 3Li and 92.5% of 7 3Li Calculate the relative atomic mass (Ar) of this sample of lithium. (2) Ar =
November 2023, Paper 1, Q2(a) (2 marks): Table 1 shows some relative masses and charges of subatomic particles. Complete table 1 by giving the missing information. (2) Electron Proton Neutron Relative
November 2023, Paper 1, Q2(b)(i) (1 mark): What is the atomic number of P in table 2? (1) A 2 B 3 C 4 D 7
November 2023, Paper 1, Q2(b)(ii) (1 mark): What is the mass number of U in table 2? (1) A 8 B 16 C 18 D 26
November 2023, Paper 1, Q2(c)(i) (2 marks): Explain, in terms of subatomic particles, why Q and R are isotopes. (2)
November 2023, Paper 1, Q2(c)(ii) (3 marks): A sample containing the isotopes Q and R has this percentage composition by mass. Q = 20.6 % R = 79.4 % Calculate the relative atomic mass (Ar) of this sample o
November 2023, Paper 2, Q1(a) (1 mark): What is the total number of electrons in one fluorine atom? (1) A 7 B 9 C 10 D 19
June 2023, Paper 1, Q7(a) (2 marks): Give the number of protons and the number of neutrons in an atom of iodine–127 (2) number of protons number of neutrons
June 2023, Paper 1, Q7(b) (3 marks): A sample of bromine contains two isotopes. • Br–79 with relative abundance 52.8 % • Br–81 with relative abundance 47.2 % Calculate the relative atomic mass (Ar)
June 2023 (R), Paper 1, Q3(a)(i) (1 mark): What is the particle labelled W? (1) A electron B neutron C nucleus D proton
June 2023 (R), Paper 1, Q3(a)(ii) (1 mark): An atom of this element contains 13 neutrons. What is the mass number of this element? (1) A 12 B 13 C 25 D 49
June 2023 (R), Paper 1, Q3(a)(iii) (1 mark): State why atoms have no overall charge. (1)
June 2023 (R), Paper 1, Q3(b)(i) (1 mark): State why both isotopes react in the same way. (1)
June 2023 (R), Paper 1, Q3(b)(ii) (3 marks): A sample of lithium contains 7.60% 6 3Li and 92.4% 7 3Li Calculate the relative atomic mass, Ar , of this sample of lithium. Give your answer to two decimal pla
June 2023 (R), Paper 2, Q1(a) (2 marks): The table lists three subatomic particles. Complete the table by giving the missing information. (2) Subatomic particle Relative mass Relative charge proton +1
January 2023, Paper 2, Q1(b)(i) (1 mark): Give the mass number of W. (1)
January 2023, Paper 2, Q1(b)(ii) (1 mark): Give a reason why X has a 3+ charge. (1)
January 2023, Paper 2, Q1(b)(iii) (2 marks): Explain why Y and Z are isotopes of the same element. (2)
January 2023 (R), Paper 1, Q6(b) (3 marks): A sample of chlorine, containing two isotopes, has this percentage composition by mass. chlorine‑35 71.2% chlorine‑37 28.8% Calculate the relative atomic mass o
June 2022, Paper 1, Q1(a) (1 mark): Name the part of the atom that contains the protons and neutrons. (1)
June 2022, Paper 1, Q1(b) (1 mark): Give the number of protons in this atom. (1)
June 2022, Paper 1, Q7(a)(i) (2 marks): State what is meant by the term isotopes. (2)
June 2022, Paper 1, Q7(a)(ii) (3 marks): Calculate the relative atomic mass (Ar) of this sample of copper. Give your answer to three significant figures. (3) Ar of copper =
June 2022 (R), Paper 1, Q1(a) (4 marks): The diagram represents an atom of an element. proton neutron electron Use numbers from the box to complete the table. You may use each number once, more than on
June 2022 (R), Paper 1, Q1(b) (2 marks): In terms of sub‑atomic particles, state a similarity and a difference for isotopes of the same element. (2) similarity difference
June 2022 (R), Paper 2, Q1(a)(i) (3 marks): Give the name of each of the sub‑atomic particles labelled P, Q and R. (3) P Q R
June 2022 (R), Paper 2, Q1(a)(ii) (1 mark): Give the name of the part of the atom labelled S. (1)
June 2022 (R), Paper 2, Q1(b) (1 mark): Give the name of this element. (1)
January 2022, Paper 1, Q5(a) (2 marks): Complete the table to show the relative mass and relative charge of a proton and a neutron. (2) Proton Electron Neutron Relative mass 1/2000 Relative charge −1
January 2022, Paper 1, Q5(b)(i) (2 marks): State the meaning of the term isotopes. (2)
January 2022, Paper 1, Q5(b)(ii) (2 marks): The symbol for an atom of one isotope of magnesium is 26 12Mg Give the number of protons, neutrons and electrons in one atom of this isotope. (2) number of prot
January 2022, Paper 1, Q5(b)(iii) (2 marks): A sample of magnesium contains these percentages of the three isotopes. Mg‑24 = 79.00 % Mg‑25 = 10.00 % Mg‑26 = 11.00 % Use this information to show that the re
January 2022 (R), Paper 1, Q4(a) (1 mark): State the meaning of the term atomic number. (1)
January 2022 (R), Paper 1, Q4(b)(i) (1 mark): Which of these is the mass number of this atom? (1) A 14 B 15 C 28 D 29
January 2022 (R), Paper 1, Q4(c) (3 marks): The table shows the composition of a sample of a different element, Y, containing three isotopes. Mass number of isotope Percentage of isotope in sample 32 95.0
November 2021, Paper 1, Q4(a)(i) (1 mark): Give the mass number of F. (1)
November 2021, Paper 1, Q4(a)(ii) (1 mark): Give the electronic configuration of G. (1)
November 2021, Paper 1, Q4(a)(iii) (2 marks): Explain why F and G are isotopes of the same element. Refer to subatomic particles in your answer. (2)
November 2021, Paper 1, Q4(b) (2 marks): A sample of carbon contains atoms of mass number 12 and 13 The table shows the percentages of these atoms in the sample. Mass number Percentage (%) 12 98.930 13
June 2021, Paper 1, Q2(a)(i) (3 marks): Complete Table 1 by giving the missing information. (3) Subatomic particle Relative mass Relative charge electron 0.0005 proton +1 neutron 1 Table 1
June 2021, Paper 1, Q2(a)(ii) (1 mark): Give the name of the part of the atom containing protons and neutrons. (1)
June 2021, Paper 1, Q2(b)(i) (1 mark): Give the letter of the species that has six electrons in its outer shell. (1)
June 2021, Paper 1, Q2(b)(ii) (1 mark): Give the mass number of Z. (1)
June 2021, Paper 1, Q2(b)(iii) (1 mark): Give the letter of the species that is a positive ion. (1)
June 2021, Paper 1, Q2(b)(iv) (1 mark): Give the letters of the two species that are isotopes of the same element. (1)
June 2021, Paper 1, Q2(c) (3 marks): A sample of neon contains two isotopes, 20Ne and 22Ne The relative abundances of the two isotopes in the sample are 20Ne 91.2% 22Ne 8.80% Calculate the relative
June 2021, Paper 2, Q1(b)(i) (1 mark): Determine the number of neutrons in a phosphorus atom with mass number 31 (1)
January 2021, Paper 1, Q8(b)(i) (3 marks): The relative percentages of each isotope in a sample of bromine are bromine-79 = 51.0% bromine-81 = 49.0% Calculate the relative atomic mass of this sample of b
January 2021, Paper 1, Q8(b)(ii) (1 mark): Give a reason why both isotopes of bromine have the same chemical properties. (1)
January 2021, Paper 2, Q1(a)(i) (1 mark): What is the name of the particle labelled Y? (1) A electron B ion C neutron D proton
January 2021, Paper 2, Q1(a)(ii) (1 mark): Give the mass number of this atom. (1)
January 2021, Paper 2, Q1(a)(iii) (1 mark): Name this element. Use the Periodic Table on page 2 to help you. (1)
January 2021, Paper 2, Q1(b) (2 marks): There are two isotopes of this element. Give one way, in terms of sub-atomic particles, that these isotopes are the same and one way that they are different. (2
November 2020 (R), Paper 2, Q2(b) (1 mark): A thallium ion has a charge of 3+ How many electrons are there in this thallium ion? (1) A 3 B 78 C 81 D 84
November 2020 (R), Paper 2, Q2(c)(i) (2 marks): Give the number of protons and the number of neutrons in one atom of the thallium-205 isotope. (2) number of protons number of neutrons
November 2020 (R), Paper 2, Q2(c)(ii) (3 marks): Calculate the relative atomic mass of this sample of thallium. Give your answer to one decimal place. (3) relative atomic mass =
January 2020, Paper 1, Q2(a) (5 marks): Complete the table by giving the missing information about this atom. (5) name of the part of this atom labelled Z number of protons in this atom number of the
January 2020, Paper 1, Q2(b) (3 marks): This element has three isotopes. The table shows the mass number and percentage abundance of each isotope in a sample of this element. Mass number Percentage ab
January 2020 (R), Paper 1, Q1(a) (1 mark): Particle Y is a proton. What is particle Z? (1) A an electron B a molecule C a neutron D a nucleus
January 2020 (R), Paper 1, Q1(b) (1 mark): Which of these has the smallest mass? (1) A an electron B a neutron C a nucleus D a proton
January 2020 (R), Paper 1, Q1(c) (1 mark): What is the mass number of this atom? (1) A 4 B 5 C 9 D 13
January 2020 (R), Paper 1, Q1(d) (1 mark): What is the atomic number of this atom? (1) A 4 B 5 C 9 D 13
January 2020 (R), Paper 1, Q1(e)(i) (1 mark): Identify the element that contains this atom. (1)
June 2019, Paper 1, Q2(c) (2 marks): An atom of element Q has 31 protons. Use this information to explain how you can determine the number of protons in an atom of element R. (2)
June 2019, Paper 2, Q1(a) (3 marks): The box gives the names of some particles. electron ion molecule neutron proton Use words from the box to label the diagram. (3)
June 2019, Paper 2, Q1(b) (1 mark): Give the mass number of this atom. (1)
June 2019, Paper 2, Q1(c) (2 marks): Complete the sentence about isotopes. (2) Isotopes are atoms that have the same number of but have a different number of .
June 2019, Paper 2, Q2(b) (3 marks): Chlorine has two isotopes of mass numbers 35 and 37 The relative percentage of each isotope in a sample of chlorine is chlorine-35 77.78% chlorine-37 22.22% Cal
June 2019 (R), Paper 2, Q2(a) (5 marks): Use information from the diagram to complete the table. The first row has been done for you. (5) atomic number 5 mass number number of neutrons group in the Per
June 2019 (R), Paper 2, Q2(b) (2 marks): Boron has two isotopes, boron‑10 and boron‑11. A sample of boron contains 18.7% of boron‑10 and 81.3% of boron‑11. Calculate the relative atomic mass of this sa

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