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Basic ideas about atoms: Eduqas A‑Level Chemistry questions

Every Eduqas A-Level Chemistry exam question on C1.2 Basic ideas about atoms, 2016–2025, with its mark scheme and examiner’s report.

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1,513 questions

  1. Q8(a)

    June 2025 · Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 8(a): Identify the type of particle emitted in this process. [1]

  2. Q8(b)

    June 2025 · Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 8(b): State how this particle would be affected by an electric field. [1]

  3. Q9(a)(i)

    June 2025 · Component 1

    2 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 9(a)(i): Explain how the dark lines form and why they get closer together. [2]

  4. Q9(a)(ii)

    June 2025 · Component 1

    3 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 9(a)(ii): The first ionisation energy of hydrogen is 1312 kJ mol–1. Calculate the wavelength of the convergence limit of the Lyman series in the atomic spectrum of hydrog

  5. Q9(b)(i)

    June 2025 · Component 1

    2 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 9(b)(i): Suggest a value for the first ionisation energy of lithium. Give your reasoning. [2]

  6. Q9(b)(ii)

    June 2025 · Component 1

    3 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 9(b)(ii): Suggest a value for the first ionisation energy of magnesium. Explain your answer. [3]

  7. Q12(a)

    June 2025 · Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 Component 1, question 12(a): Write the electronic structure of a chromium atom. [1]

  8. Q3

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 3: State what happens to the atomic number and the mass number of a nucleus when it emits a β-particle. [1]

  9. Q4

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 4: State why only the Lyman series is used to determine the ionisation energy for a hydrogen atom.  [1]

  10. Q9(a)

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 9(a): 135Pm decays by positron emission. Give the symbol and mass number of the element formed. [1] …………… …………………..

  11. Q9(b)

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 9(b): Isotopes of promethium, such as 135Pm, can be synthesised and their half-lives can be studied. State what is meant by the term half-life. [1]

  12. Q9(c)(i)

    June 2025 · AS Component 1

    2 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 9(c)(i): Identify the mass reading that has the largest percentage error. Calculate this percentage error. Assume that it is based on one weighing only. [2] Percentage

  13. Q9(c)(ii)

    June 2025 · AS Component 1

    3 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 9(c)(ii): Plot a graph of the mass of sample against time. Label the axes and choose a suitable scale. [3]

  14. Q9(c)(iii)

    June 2025 · AS Component 1

    2 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 9(c)(iii): Use the graph to determine the half-life of the isotope. Show clearly how you get your answer.  [2] Half-life = s

  15. Q12(a)

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 12(a): Give the electronic configuration of a nitrogen atom. [1]

  16. Q12(b)

    June 2025 · AS Component 1

    2 marksC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 12(b): State and explain the general trend in the first ionisation energy across Period 2. [2]

  17. Q12(c)(i)

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 12(c)(i): Explain why the second ionisation energy is greater than the first ionisation energy. [1]

  18. Q12(c)(ii)

    June 2025 · AS Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2025 AS Component 1, question 12(c)(ii): Explain why the fourth ionisation energy is slightly higher than expected. [1]

  19. Q1(a)

    June 2024 · Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2024 Component 1, question 1(a): Write the electronic structure of the Na+ ion. [1]

  20. Q1(b)

    June 2024 · Component 1

    1 markC1.2 Basic ideas about atoms
    The whole paper ↗
    June 2024 Component 1, question 1(b): Draw the shape of the orbital that contains the outermost electron of the Na+ ion. [1]
All 98 questions on Basic ideas about atoms, as a list
  1. June 2025, Component 1, Q8(a) (1 mark): Identify the type of particle emitted in this process. [1]
  2. June 2025, Component 1, Q8(b) (1 mark): State how this particle would be affected by an electric field. [1]
  3. June 2025, Component 1, Q9(a)(i) (2 marks): Explain how the dark lines form and why they get closer together. [2]
  4. June 2025, Component 1, Q9(a)(ii) (3 marks): The first ionisation energy of hydrogen is 1312 kJ mol–1. Calculate the wavelength of the convergence limit of the Lyman series in the atomic spectrum of hydrog
  5. June 2025, Component 1, Q9(b)(i) (2 marks): Suggest a value for the first ionisation energy of lithium. Give your reasoning. [2]
  6. June 2025, Component 1, Q9(b)(ii) (3 marks): Suggest a value for the first ionisation energy of magnesium. Explain your answer. [3]
  7. June 2025, Component 1, Q12(a) (1 mark): Write the electronic structure of a chromium atom. [1]
  8. June 2025, AS Component 1, Q3 (1 mark): State what happens to the atomic number and the mass number of a nucleus when it emits a β-particle. [1]
  9. June 2025, AS Component 1, Q4 (1 mark): State why only the Lyman series is used to determine the ionisation energy for a hydrogen atom.  [1]
  10. June 2025, AS Component 1, Q9(a) (1 mark): 135Pm decays by positron emission. Give the symbol and mass number of the element formed. [1] …………… …………………..
  11. June 2025, AS Component 1, Q9(b) (1 mark): Isotopes of promethium, such as 135Pm, can be synthesised and their half-lives can be studied. State what is meant by the term half-life. [1]
  12. June 2025, AS Component 1, Q9(c)(i) (2 marks): Identify the mass reading that has the largest percentage error. Calculate this percentage error. Assume that it is based on one weighing only. [2] Percentage
  13. June 2025, AS Component 1, Q9(c)(ii) (3 marks): Plot a graph of the mass of sample against time. Label the axes and choose a suitable scale. [3]
  14. June 2025, AS Component 1, Q9(c)(iii) (2 marks): Use the graph to determine the half-life of the isotope. Show clearly how you get your answer.  [2] Half-life = s
  15. June 2025, AS Component 1, Q12(a) (1 mark): Give the electronic configuration of a nitrogen atom. [1]
  16. June 2025, AS Component 1, Q12(b) (2 marks): State and explain the general trend in the first ionisation energy across Period 2. [2]
  17. June 2025, AS Component 1, Q12(c)(i) (1 mark): Explain why the second ionisation energy is greater than the first ionisation energy. [1]
  18. June 2025, AS Component 1, Q12(c)(ii) (1 mark): Explain why the fourth ionisation energy is slightly higher than expected. [1]
  19. June 2024, Component 1, Q1(a) (1 mark): Write the electronic structure of the Na+ ion. [1]
  20. June 2024, Component 1, Q1(b) (1 mark): Draw the shape of the orbital that contains the outermost electron of the Na+ ion. [1]
  21. June 2024, Component 1, Q10(b)(i) (2 marks): The most stable isotope of actinium is 227Ac. It can decay by emission of either an alpha or beta particle. Identify the isotopes formed in each case. [2] Produ
  22. June 2024, Component 1, Q10(d)(i) (2 marks): A 10.0 mg sample of americium-238 is left for 294 minutes. Calculate the mass of plutonium present after 294 minutes. [2] Mass = mg
  23. June 2024, Component 1, Q10(d)(ii) (1 mark): Suggest why it is important to know the half-life of the isotope formed when calculating the mass of plutonium. [1]
  24. June 2024, Component 1, Q15(a) (1 mark): State what is meant by the term first ionisation energy. [1]
  25. June 2024, Component 1, Q15(b) (5 marks): The second ionisation energies of four elements are given below. The elements are lithium, magnesium, silicon and sodium but not in that order. 1450 kJ mol–1 15
  26. June 2024, Component 1, Q15(c)(ii) (1 mark): Suggest a value for the first ionisation energy of calcium. Give a reason for your answer. [1]
  27. June 2024, Component 2, Q7(d)(ii) (1 mark): Ultraviolet light causes initial homolytic fission of the bromine molecule into two bromine radicals. State the number of outer electrons present in a bromine r
  28. June 2024, AS Component 1, Q3(a) (1 mark): Give the meaning of the term orbital. [1]
  29. June 2024, AS Component 1, Q3(b) (1 mark): Identify the shape of a p-orbital by circling the correct diagram. [1] z z z y y y x x x
  30. June 2024, AS Component 1, Q6(c) (3 marks): The first ionisation energy of argon is 1521 kJ mol–1. Calculate the frequency of the high energy photon needed to ionise an Ar atom to form an Ar+ ion. Give yo
  31. June 2024, AS Component 1, Q6(d)(ii) (2 marks): Write an equation for the formation of 218Po by the radioactive decay of 222Rn. [2]
  32. Autumn 2021, Component 1, Q9(a) (2 marks): The reactivity of Group 1 elements increases down the group as the first ionisation energy decreases. Explain why the first ionisation energy of Group 1 element
  33. Autumn 2021, Component 1, Q9(d)(i) (1 mark): Iodine-131 decays by emission of a β– particle. Identify the isotope formed. [1] Element Mass Number
  34. Autumn 2021, Component 1, Q9(d)(ii) (1 mark): State what is meant by β– radiation. [1]
  35. Autumn 2021, Component 1, Q9(d)(iii) (2 marks): Calculate the level of radioactivity due to iodine-131 after 32 days. [2] Level of radioactivity due to iodine-131 = Bq
  36. Autumn 2021, Component 1, Q9(d)(iv) (2 marks): Suggest which of the two isotopes was released in greater amounts during the accident. Use the data in the table to justify your answer.  [2]
  37. Autumn 2021, Component 1, Q11(a) (1 mark): Give the electronic structure of a copper atom.  [1]
  38. Autumn 2021, Component 1, Q15(c) (2 marks): The lilac colour of the flame test is caused by the emission spectrum of an ion. Describe how the emission spectrum of hydrogen atoms can be used to find the fi
  39. Autumn 2020, Component 1, Q3(a) (1 mark): Identify the type of radioactive decay occurring. [1]
  40. Autumn 2020, Component 1, Q3(b) (2 marks): A sample of 0.276 g of 24Na decays for 45 hours. Calculate the mass of magnesium-24 produced in this time. [2] Mass = ……… ………………… g
  41. Autumn 2020, Component 1, Q8(c)(i) (1 mark): Give the equation for the third ionisation energy of magnesium. [1]
  42. Autumn 2020, Component 1, Q8(c)(ii) (2 marks): Explain why the tenth ionisation energy of sodium is much larger than the tenth ionisation energy of magnesium. [2]
  43. Autumn 2020, Component 1, Q8(c)(iii) (2 marks): The plot for the log of the second ionisation energy of sodium is missing from the graph. Estimate its value and hence calculate an approximate second ionisatio
  44. Autumn 2020, Component 1, Q11(c) (6 marks): When an electrical discharge is passed through hydrogen gas, the atoms emit light and other frequencies of electromagnetic radiation. These form the emission sp
  45. Autumn 2020, AS Component 1, Q1 (1 mark): Complete the electronic configuration of the Se2– ion. [1] 1s22s2
  46. Autumn 2020, AS Component 1, Q4 (1 mark): A radioactive isotope has a half-life of 4 hours. Calculate the time needed for 4.0 g of the isotope to decay to 0.5 g. [1] Time = hours
  47. Autumn 2020, AS Component 1, Q8(a) (2 marks): State the meaning of the term molar first ionisation energy. [2]
  48. Autumn 2020, AS Component 1, Q8(b) (6 marks): Students using a spectrometer observed lines from a hydrogen lamp in the visible part of the spectrum. One student said that the frequencies of the lines could
  49. Autumn 2020, AS Component 1, Q8(c) (4 marks): A line in a spectrum has a wavelength of 550 nm. Calculate the energy change, in kJ mol–1, that corresponds to this line. [4] Energy change = kJ mol–1
  50. Autumn 2020, AS Component 1, Q8(d)(i) (2 marks): Explain the difference in the values for sodium and magnesium. [2]
  51. Autumn 2020, AS Component 1, Q8(d)(ii) (2 marks): Explain the difference in the values for sodium and potassium. [2]
  52. June 2019, Component 1, Q1 (1 mark): Complete the diagram below, using arrows to represent electrons, to show the electron arrangement for an atom of cobalt. [1] 3s 3p 3d 4s [Ne]
  53. June 2019, Component 1, Q9(c)(i) (2 marks): Explain why this energy is emitted. [2]
  54. June 2019, Component 1, Q9(c)(ii) (3 marks): The first ionisation energy of hydrogen is 1316 kJ mol−1. Calculate the wavelength of the convergence limit of the Lyman series for hydrogen in nm. [3] Waveleng
  55. June 2019, Component 1, Q11(a) (1 mark): Selenium is an element in the p-block of the Periodic Table. What information regarding the electronic structure of the selenium atom can be deduced from this s
  56. June 2019, Component 1, Q11(c)(i) (2 marks): The half-life of selenium-75 is 120 days. Samples are provided that have eight times higher concentration of selenium-75 atoms than the minimum needed for use a
  57. June 2019, Component 1, Q11(c)(ii) (2 marks): Selenium-75 does not emit alpha particles when it decays. Explain why this is important for its use as a medical tracer. [2]
  58. June 2019, Component 2, Q13(c)(i) (3 marks): A species of sea slug produces an alarm pheromone which is a mixture of three compounds. One of these compounds is Navenone B. H H H H O C C C C C C C C C CH3 H
  59. June 2019, AS Component 1, Q1 (1 mark): Complete the electronic structure for the Br – ion. 1 [1] 1s22s22p63s2
  60. June 2019, AS Component 1, Q2 (1 mark): Complete the equation to show what happens when 28 P decays by positron emission. [1] 15 28 P 0 β + 15 +1
  61. June 2019, AS Component 1, Q5 (1 mark): An element absorbs green light with a wavelength of 500 nm. Another element absorbs red light. Suggest a value for the wavelength of this absorption. [1] nm
  62. June 2019, AS Component 1, Q9(a) (1 mark): Write the equation that corresponds to the molar first ionisation energy of an element. Use X to represent the element. [1]
  63. June 2019, AS Component 1, Q9(b)(i) (2 marks): Explain why first ionisation energies generally increase in value as a period is crossed from left to right. [2]
  64. June 2019, AS Component 1, Q9(b)(ii) (2 marks): In which group of the Periodic Table is the element shown as Y? Explain how you reached this conclusion. [2]
  65. June 2019, AS Component 1, Q9(b)(iii) (1 mark): On the graph plot the expected molar first ionisation energy for the next element in the Periodic Table. Label this point Z. [1]
  66. June 2019, AS Component 1, Q10(c) (4 marks): Street lights containing sodium vapour emit yellow light. [4]
  67. June 2018, Component 1, Q1(a) (1 mark): Give the electronic structure of an atom of phosphorus. [1]
  68. June 2018, Component 1, Q1(b) (2 marks): Explain why the first ionisation energy of phosphorus is greater than that of sulfur. [2]
  69. June 2018, Component 1, Q9(b) (3 marks): The first ionisation energy of caesium is 376 kJ mol–1. This value can be found from the frequency of a line in the atomic spectrum of caesium. Calculate the fr
  70. June 2018, Component 1, Q12(a) (1 mark): Give the numbers of protons and neutrons in the nucleus of a fluorine-18 atom. [1] Protons …………… ………………… Neutrons …………… …………………
  71. June 2018, Component 1, Q12(b) (2 marks): This radioisotope decays to form oxygen-18 only. Identify the type of radiation that must be emitted for this change to occur and identify any other type(s) of
  72. June 2018, Component 1, Q12(c)(ii) (4 marks): The half-life of the fluorine-18 isotope is 110 minutes, and the original fluorine sample contained four fluorine-18 atoms for every fluorine-19 atom. Find the
  73. June 2018, Component 1, Q12(d)(i) (2 marks): Sketch a diagram showing the successive ionisation energies for oxygen. Show all eight ionisation energies. [2] 1 2 3 4 5 6 7 8 Number of electrons removed
  74. June 2018, Component 1, Q12(d)(ii) (2 marks): Explain how this diagram gives information regarding the position of the element in the Periodic Table. [2]
  75. June 2018, Component 2, Q10(d)(iv) (2 marks): Compounds A, B and C are colourless and were detected during HPLC by using ultraviolet radiation. Absorption maximum / nm Compound 202.1 C 212.2 B 273.4 A State
  76. June 2018, AS Component 1, Q1 (1 mark): Complete the electronic structure of a bromine atom, Br. [1] 1s2 2s2 2p6
  77. June 2018, AS Component 1, Q5 (2 marks): Complete the diagram to show how α-, β- and γ-radiation are affected by an electric field. [2] beam containing α-, β- and γ-radiation
  78. June 2017, Component 1, Q1 (1 mark): Show the electronic structure of silicon using arrows in boxes. [1]
  79. June 2017, Component 1, Q2 (1 mark): Write the equation for the second ionisation energy of boron. [1]
  80. June 2017, Component 1, Q5 (2 marks): In the atomic emission spectrum of hydrogen the frequency of the convergence point of the Lyman series is 3.28 × 1015 Hz. Calculate the ionisation energy of hyd
  81. June 2017, Component 1, Q12(a) (1 mark): The main radioactivity detected was beta radiation. Give a reason why it is unlikely that alpha radiation would be detected from a solution contained in a sampl
  82. June 2017, Component 1, Q12(b) (1 mark): State what is meant by gamma radiation. [1]
  83. June 2017, Component 1, Q12(c) (1 mark): Give a reason why radioactivity is harmful to living things. [1]
  84. June 2017, Component 1, Q12(d) (1 mark): Arsenic-74 can decay either by emission of a beta particle or by emission of a positron. Identify the isotope formed by emission of a positron. [1] Element Mass
  85. June 2017, Component 1, Q12(e)(ii) (2 marks): Identify which original isotope is present in the greatest concentration in the solution. Explain your answer. [2]
  86. June 2017, Component 1, Q12(f) (2 marks): After studying the data, it was suggested that the affected area around the reactor would be safe after 60 years as this is twice the half-life of the longest l
  87. June 2017, AS Component 1, Q1 (1 mark): Complete the electronic configuration for the ion Ni2+. [1] 1s2 2s2
  88. June 2017, AS Component 1, Q2 (1 mark): The half-life of a radioactive isotope is 12 days. If a 3.0 g sample of the isotope is left for 24 days, what mass of the isotope will remain? [1] Mass = g
  89. June 2017, AS Component 1, Q10(a)(i) (2 marks): State the meaning of the term standard molar first ionisation energy. [2]
  90. June 2017, AS Component 1, Q10(a)(ii) (4 marks): The graph below shows the logarithm of the first eight successive ionisation energies for element X. 5.0 4.0 3.0 2.0 0 0 1 2 3 4 5 6 7 8 Number of electron lost
  91. June 2017, AS Component 1, Q10(b)(i) (6 marks): Discuss whether you agree with this student’s suggestion. You should include an explanation of how spectral lines are produced and how they can be used to deter
  92. June 2017, AS Component 1, Q10(b)(ii) (3 marks): A spectral line with a frequency of 3.28 × 1015 Hz was formed when an atom of hydrogen was ionised. Calculate the first ionisation energy of hydrogen in kJ mol−
  93. June 2016, AS Component 1, Q1 (1 mark): Complete the electronic structure for a vanadium, V, atom. [1] 1s22s2
  94. June 2016, AS Component 1, Q3 (1 mark): Complete the equation below to show one form of radioactive decay. [1] 23 Mg + e+ 12
  95. June 2016, AS Component 1, Q6 (1 mark): Draw the shape of a 2p orbital on the axes below. [1]
  96. June 2016, AS Component 1, Q12(a) (6 marks): Discuss how far you agree with David’s statement and correct any errors which he has made. You should include the chemical principles involved. [6 QER]
  97. June 2016, AS Component 1, Q12(c)(i) (3 marks): A line in a visible spectrum was observed at a wavelength of 500 nm. Calculate the energy involved in the formation of this line. Give your answer with its unit
  98. June 2016, AS Component 1, Q12(c)(ii) (1 mark): A line in another spectrum was found to have a higher energy associated with its formation so that it was no longer visible. In which part of the electromagneti

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