Particles in the atom and atomic radius: past paper questions

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

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

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

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

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

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

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• 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?

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

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

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• 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?

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• 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.

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

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

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• 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.

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• Question 4May/June 2024, paper 11Multiple choice1 mark

  Which statement about ${}_{53}^{131}\text{I}$ is correct?

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• 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.

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• 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, ${}^{68}\text{X}$.

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• Question 2May/June 2025, paper 12Multiple choice1 mark

  How many neutrons are contained in an atom of iron with a mass number of 60?

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• Question 3May/June 2024, paper 13Multiple choice1 markHas a diagram

  What is the total number of protons, neutrons and electrons present in an ammonium ion with a relative formula mass of 21?

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• Question 2May/June 2026, paper 22Structured6 marksHas a diagram

  Protons, neutrons and electrons are released with the same velocity from a source. Figure 2.1 shows the movement of two of these types of particle when they travel between oppositely charged plates.

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• Question 14May/June 2025, paper 12Multiple choice1 markHas a diagram

  A helium ion contains two protons, two neutrons and one electron. This helium ion and a proton are passed separately through a uniform electric field. The particles are travelling at the same velocity.

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• Question 1May/June 2024, paper 22Structured15 marksHas a diagram

  Complete Table 1.1 using relevant information from the Periodic Table.

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• Question 17Oct/Nov 2023, paper 13Multiple choice1 mark

  Which row about silicon, Si, and magnesium, Mg, and their ions is correct?

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• Question 2May/June 2026, paper 23Structured9 marks

  Group 18 elements exist as colourless gases at room temperature and pressure.

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• Question 23May/June 2025, paper 13Multiple choice1 markHas a diagram

  In which row do the particles increase in size?

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• Question 1May/June 2023, paper 11Multiple choice1 mark

  Element X has six more protons than element Y. Which statement must be correct?

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• Question 2May/June 2025, paper 22Structured10 marks

  A sample of iron contains three different isotopes and has a relative atomic mass, $A_{\text{r}}$, of 55.8. Define relative atomic mass.

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• Question 3May/June 2023, paper 11Multiple choice1 mark

  Three statements about potassium and chlorine and their ions are listed. 1 The atomic radius of a potassium atom is greater than the atomic radius of a chlorine atom. 2 The first ionisation energy of potassium is greater than the first ionisation energy of chlorine.

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• Question 1May/June 2025, paper 23Structured10 marks

  The chemical properties of an element are related to the electronic configuration of its atoms. Give the full electronic configuration of a fluorine atom.

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• Question 1May/June 2023, paper 12Multiple choice1 markHas a diagram

  When chlorine gas is analysed in a mass spectrometer ${}^{35}{\text{Cl}}^{+}$ ions are detected. Which row is correct?

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• Question 1May/June 2023, paper 21Structured13 marksHas a diagram

  Tellurium is an element in Group 16. The most common isotope of tellurium is ${}^{130}\mathrm{T}\mathrm{e}$. Its electronic configuration is $[\mathrm{K}\mathrm{r}]4{\mathrm{d}}^{10}5{\mathrm{s}}^{2}5{\mathrm{p}}^4$.

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