Atomic structure: past paper questions

Where the questions come from

• Question 1May/June 2026, paper 11Multiple choice1 markHas a diagram

  Which diagram shows the trend in radius for the five species, ${\text{O}}^{2-}$, ${\text{F}}^{-}$, $\text{Ne}$, ${\text{Na}}^{+}$, ${\text{Mg}}^{2+}$?

  Try this question
• Question 1Oct/Nov 2025, paper 11Multiple choice1 mark

  What is the electronic configuration for the particle ${}_{13}^{27}{\text{Al}}^{+}$?

  Try this question
• Question 1Oct/Nov 2024, paper 11Multiple choice1 mark

  In this question Q is used to represent a halogen atom. Magnesium and calcium each form a compound with chlorine and a compound with bromine.

  Try this question
• Question 1Oct/Nov 2023, paper 11Multiple choice1 mark

  Sodium azide, ${\mathrm{N}\mathrm{a}\mathrm{N}}_3$ is an explosive used to inflate airbags in cars when they crash. It consists of positive sodium ions and negative azide ions. What are the numbers of electrons in the sodium ion and the azide ion?

  Try this question
• Question 2May/June 2026, paper 11Multiple choice1 mark

  Why is the first ionisation energy of sulfur lower than that of phosphorus?

  Try this question
• Question 2Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  The data in the table gives the 5th to the 10th ionisation energies of three elements from Period 3 of the Periodic Table.

  Try this question
• Question 2Oct/Nov 2024, paper 11Multiple choice1 mark

  Compound X contains two elements, Y and Z. Element Y is in Period 2 of the Periodic Table. In one atom of element Y, the p sub-shell has all three orbitals occupied; only one of these three orbitals is fully occupied. Element Z is in Period 3 of the Periodic Table.

  Try this question
• Question 2Oct/Nov 2023, paper 11Multiple choice1 mark

  The graph shows the variation of the first ionisation energy with proton number for some elements. The letters used are not the actual symbols for the elements. Which statement about the elements is correct?

  Try this question
• Question 3May/June 2026, paper 12Multiple choice1 markHas a diagram

  Which row correctly describes the ion ${}_{16}^{35}{\text{S}}^{2-}$?

  Try this question
• Question 16Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  The atomic radii and ionic radii for three elements in Period 3 are shown.

  Try this question
• Question 40Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  The diagram shows the mass spectrum of a sample of chlorine. Peaks V, W, X, Y and Z are labelled. Which statements about this spectrum are correct?

  Try this question
• Question 1Oct/Nov 2023, paper 12Multiple choice1 mark

  Which particle contains 8 protons, 9 neutrons and 10 electrons?

  Try this question
• Question 4May/June 2026, paper 12Multiple choice1 markHas a diagram

  Element X has a higher first ionisation energy than element Y. Two students state one factor that helps to explain this.

  Try this question
• Question 1Oct/Nov 2024, paper 12Multiple choice1 mark

  Which species contains a different number of electrons from the other three?

  Try this question
• Question 2Oct/Nov 2023, paper 12Multiple choice1 mark

  The second ionisation energy of oxygen is greater than the second ionisation energy of fluorine. Which factor explains this difference?

  Try this question
• Question 40May/June 2026, paper 12Multiple choice1 markHas a diagram

  The mass spectrum of an alloy of copper and gold is shown. Which expression can be used to calculate the relative atomic mass, $A_r$, of copper present in this sample?

  Try this question
• Question 1Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  What is the electrons in boxes notation for the ${\text{Fe}}^{3+}$ ion?

  Try this question
• Question 2Oct/Nov 2024, paper 12Multiple choice1 mark

  Which factor causes helium to have a higher first ionisation energy than hydrogen?

  Try this question
• Question 18Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  Which row gives the best description of the variations in the melting points and the first ionisation energies of the elements in Period 3 from sodium to argon?

  Try this question
• Question 1May/June 2026, paper 13Multiple choice1 mark

  What is the electronic configuration of ${\text{Cr}}^{3+}$?

  Try this question
• Question 2Oct/Nov 2025, paper 12Multiple choice1 mark

  Which equation has an energy change that is equal to the first ionisation energy of bromine?

  Try this question
• Question 19Oct/Nov 2023, paper 12Multiple choice1 mark

  X and Y are atoms of different elements in Period 3 of the Periodic Table. Neither X nor Y is argon. X is a non-metal.

  Try this question
• Question 4May/June 2026, paper 13Multiple choice1 mark

  The ${}^{68}\text{Ge}$ isotope undergoes a natural radioactive process to give an isotope of a different element, ${}^{68}\text{X}$.

  Try this question
• Question 7Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  $\text{X}$ and $\text{Y}$ are different elements in Period 3. Atoms of $\text{X}$ and $\text{Y}$ each have only one completely filled orbital in their highest occupied energy sub-shell. $\text{Y}$ has a greater first ionisation energy than $\text{X}$.

  Try this question
• Question 40Oct/Nov 2024, paper 13Multiple choice1 markHas a diagram

  The diagram shows the mass spectrum of a sample of chlorine. Peaks V, W, X, Y and Z are labelled. [Diagram: Mass spectrum of chlorine showing peaks V, W, X, Y and Z] Which statements about this spectrum are correct?

  Try this question
• Question 40Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  Oxygen has three stable isotopes, ${}^{16}\text{O}$, ${}^{17}\text{O}$ and ${}^{18}\text{O}$. All three isotopes are present in a sample of oxygen gas, ${\text{O}}_2$, which was analysed using a mass spectrometer. How many peaks associated with the ${\text{O}}_2^{+}$ ion would be expected?

  Try this question
• Question 1May/June 2026, paper 21Structured17 marksHas a diagram

  Complete the dot-and-cross diagram in Figure 1.1 to show the arrangement of outer shell electrons in a molecule of ${\mathrm{S}\mathrm{F}}_6$.

  Try this question
• Question 17Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  Sodium and sulfur react together to form sodium sulfide, ${\text{Na}}_2\text{S}$. How do the atomic radius and ionic radius of sodium compare with those of sulfur?

  Try this question
• Question 1Oct/Nov 2024, paper 21Structured16 marks

  Cobalt, rhodium and iridium are metals in the same group of the Periodic Table. The shorthand electronic configuration of cobalt is [Ar]$3{\text{d}}^{7}4{\text{s}}^2$. Identify what is meant by [Ar] by giving its full electronic configuration.

  Try this question
• Question 1May/June 2026, paper 22Structured14 marks

  Oxygen reacts with many elements. State the total number of electrons that occupy the 2p sub-shell in an oxygen atom.

  Try this question