Particles in the atom and atomic radius: past paper questions
Real questions on particles in the atom and atomic radius
The newest 20 of 99 written questions. Open one to see it on the real paper.
- 9701/21 · October/November 2025 · Q1a(i)[1]
The most common isotope of Cr is chromium-52. Determine the number of protons, neutrons and electrons in an atom of chromium-52.
See it on the paper → - 9701/21 · October/November 2025 · Q2a(i)[2]
Explain the trend shown in the atomic radii of the Period 3 elements Na to Cl . (i)
See it on the paper → - 9701/21 · October/November 2025 · Q2a(ii)[2]
Explain why there is a large difference in the ionic radii of Al and P. (ii)
See it on the paper → - 9701/21 · October/November 2025 · Q2b(i)[2]
Complete Table 2.1.
See it on the paper → - 9701/21 · October/November 2025 · Q2b(ii)[1]
State why there is no data given in row B for Al 2 O 3 and SiO 2 .
See it on the paper → - 9701/21 · October/November 2025 · Q2c(i)[1]
Write an equation for the reaction of Na 2 O with dilute hydrochloric acid.
See it on the paper → - 9701/21 · October/November 2025 · Q2c(ii)[1]
Construct an equation for the reaction of Al 2 O 3 with a base to form NaAl O 2 .
See it on the paper → - 9701/22 · October/November 2025 · Q1b(i)[1]
Complete the full electronic configuration of manganese. 3d 5 4s 2
See it on the paper → - 9701/22 · October/November 2025 · Q4a(iii)[1]
Reaction 1 is initiated by the bond fission of Cl 2 . State the type of bond fission shown in the initiation step.
See it on the paper → - 9701/23 · October/November 2025 · Q1b(i)[1]
Complete the full electronic configuration of chromium. 3d 5 4s 1 (i)
See it on the paper → - 9701/23 · October/November 2025 · Q1b(ii)[1]
Deduce the total number of unpaired electrons in an atom of chromium.
See it on the paper → - 9701/52 · October/November 2025 · Q2a(i)[1]
Suggest a suitable piece of apparatus to transfer 25.00 cm 3 of the lake water sample to the beaker in step 1.
See it on the paper → - 9701/52 · October/November 2025 · Q2a(ii)[1]
0.100 mol dm –3 Ba(OH) 2 (aq) is an irritant to skin and eyes. Other than wearing safety goggles, state one safety precaution that the student should take when conducting this experiment.
See it on the paper → - 9701/52 · October/November 2025 · Q2b(ii)[1]
Identify the independent variable in this experiment.
See it on the paper → - 9701/22 · May/June 2025 · Q2d[2]
Complete Table 2.2 to show information about particles in one ion of 56 Fe 3+ . Table 2.2 number of particles present in one ion of 56 Fe 3+ particle electrons 30
See it on the paper → - 9701/22 · May/June 2025 · Q2e[2]
The atomic radius of iron is 1.26 × 10 –10 m. Suggest the change to the radius, if any, after an iron atom reacts to produce an Fe 3+ ion. Explain your answer.
See it on the paper → - 9701/43 · May/June 2025 · Q5a(i)[1]
Complete the electronic configurations of a Cu + ion and a Cu 2+ ion. Cu + ion: [Ar] 2+
See it on the paper → - 9701/43 · May/June 2025 · Q5a(ii)[1]
Explain why transition elements have variable oxidation states.
See it on the paper → - 9701/43 · May/June 2025 · Q5b(i)[1]
A few drops of NH 3 (aq) are added to CuSO 4 (aq). Describe any observations made.
See it on the paper → - 9701/51 · May/June 2025 · Q1a[2]
• wearing chemically resistant gloves using a fume hood (a) Use the information in Table 1.1 to suggest why the following safety precautions are used. •
See it on the paper →
What examiners said
Many answers did not address the question, with little mention of the massive nucleus, or the relative position and mass of the electrons.
— Examiner report, February/March 2025, 9701/22 Q2(c)(i) (Cambridge)
The decrease in ionic radius from P3─ to S2─ and Cl─ was well answered. Many correct explanations included mention of an increased attraction of the outer electron to the nucleus resulting from an increased nuclear charge with each ionic species having the same shielding.
— Examiner report, October/November 2023, 9701/21 Q1(b)(ii) (Cambridge)
The variation in atomic radius from silicon to sulfur was, in general, well known.
— Examiner report, October/November 2023, 9701/22 Q1(a)(i) (Cambridge)
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