AQA GCSE Chemistry Chemistry Paper 1 (Higher), 2024: Question 3
8 marks · Standard Demand difficulty · Short Answer
Identify early atomic models, compare the plum pudding model to the modern nuclear model, and define isotopes.
Practise this questionQuestion
Question text
03 This question is about models of the atom.
Figure 2 shows two early models of the atom.
Figure 2
03.1 Name the models of the atom shown in Figure 2.
[2 marks]
Model A
Model B
03.2 Compare model A with the model of the atom used today.
Use Figure 2.
[4 marks]
03.3 Chadwick’s experiments showed the existence of neutrons in an atom.
This led to an understanding of isotopes.
Define the term ‘isotopes’.
Refer to subatomic particles in your answer.
[2 marks]
Mark scheme
Show the mark scheme
Question 3
AO /
Question Answers Extra information Mark
Spec. Ref.
03.1 (model A) plum pudding allow Thomson (model) 1 AO1
4.1.1.3
(model B) Bohr allow nuclear (model) 1
allow planetary (model)– – –
allow Rutherford-Bohr (model)
AO /
Question Answers Mark
Spec. Ref.
03.2 Level 2: Scientifically relevant features are identified; the way(s) in 3–4 AO1
which they are similar / different is made clear and (where 4.1.1.3
appropriate) the magnitude of the similarity / difference is noted.
Level 1: Relevant features are identified and differences noted. 1–2
No relevant content 0
Indicative content
Similarities
• both contain electrons
• both are neutral overall
Differences
• model A has no nucleus
or
the model used today has a nucleus
• model A has no protons
or
the model used today has protons
• model A has no neutrons
or
the model used today has neutrons
• model A has positive charge spread throughout the atom
or
model A is a ball of positive charge
• the model used today has the positive charge in the centre
• model A the electrons are distributed randomly
• the model used today has electrons in shells / energy levels
• the mass was spread throughout model A
• the mass is concentrated at the centre of the model used today
• model A does not have empty space
– – –
• model used today is mostly empty space
AO /
12 Question Answers Extra information Mark
Spec. Ref.
03.3 atoms with the same number of allow atoms of the same 1 AO1
protons element 4.1.1.5
allow atoms with the same
atomic number
ignore references to electrons
with different numbers of 1
neutrons
Total Question 3 8
How to answer it
The History of Atomic Models & Isotopes
What this question tests
This question assesses your ability to identify historical models of the atom, compare the early "Plum Pudding" model with our modern understanding, and provide a precise scientific definition of isotopes using subatomic particle terminology.
Naming the Atomic Models
💡 Key Knowledge
- Model A: A sphere of positive charge with electrons embedded in it.
- Model B: Electrons orbiting a central nucleus in specific shells/energy levels.
✅ Correct Answers
- Model A: Plum pudding (model)
- Model B: Bohr (model)
🧠 Exam Technique
For Model B, the examiner also accepts "nuclear model" or "planetary model." However, "Bohr model" is the most specific name for the version showing electrons in distinct shells.
Comparing Model A to the Modern Model
4 Marks - Comparison Skills
💡 Key Knowledge: The Modern Model
The model used today (the Nuclear Model) features a tiny, dense nucleus containing protons and neutrons, with electrons in shells, and is mostly empty space.
✅ How to get 4 Marks
To reach Level 2 (3-4 marks), you must identify both similarities and differences.
- Similarity: Both contain electrons.
- Similarity: Both are neutral overall.
- Difference: Model A has no nucleus, whereas the modern model has a central nucleus.
- Difference: Model A is a "ball of positive charge," whereas the modern model has positive charge (protons) in the centre.
- Difference: Model A has no empty space, whereas the modern model is mostly empty space.
🧠 Examiner Commentary
Top-level students use comparative language like "whereas" or "however" to link their points. Many students lose marks by only listing differences and forgetting that both models agree that atoms contain negative electrons!
❌ Common Errors
- Claiming Model A has a nucleus (it doesn't!).
- Forgetting to mention that the modern model contains neutrons (discovered later by Chadwick).
- Describing Model B instead of the "model used today" (though they are very similar, focus on the presence of neutrons).
Defining Isotopes
✅ Correct Answer
Isotopes are atoms with the same number of protons but different numbers of neutrons.
🧠 Exam Technique
The question specifically asks you to refer to subatomic particles. If you just say "atoms of the same element with different masses," you might only get 1 mark. Always mention protons and neutrons to be safe.
❌ Common Errors
Do not mention electrons in your definition. While isotopes of the same element have the same number of electrons, it is the neutrons that make them isotopes. Mentioning "different numbers of electrons" will lose you the mark.
📐 Quick Recall Table
| Particle | Relative Charge | Relative Mass |
|---|---|---|
| Proton | +1 | 1 |
| Neutron | 0 | 1 |
| Electron | -1 | Very small (1/2000) |
Topics
Chemistry · C1: Atomic Structure and the Periodic Table
Question and mark scheme from the AQA GCSE Chemistry examination, Chemistry Paper 1 (Higher), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.