AQA GCSE Chemistry Chemistry Paper 1 (Higher), 2023: Question 1

9 marks · Standard Demand difficulty · Short Answer

This multi-part question assesses knowledge of atomic models, the history of subatomic particle discovery, periodic table trends for new elements, the scientific process of peer review, and the calculation of relative atomic mass from isotopic abundance.

Practise this question

Question

The image contains five sub-questions (01.1 to 01.5) regarding atomic structure. Question 01.1 shows a diagram of the plum pudding model as a circle with a plus sign in the center and four small minus signs distributed around it. Question 01.5 includes a table showing two isotopes of element R with mass numbers 6 and 7 and their respective percentage abundances of 7.6% and 92.4%.
Question text

01 Discoveries in chemistry led to a better understanding of atomic structure.

01.1 Atoms were originally thought to be tiny spheres that could not be divided.

The plum pudding model of the atom was then developed.

Figure 1 represents the plum pudding model of the atom.

Figure 1

Describe the plum pudding model of the atom.

[2 marks]

01.2 Atoms contain electrons, neutrons and protons.

Write these three particles in order of their discovery.

[1 mark]

Earliest

Latest

Very few atoms of the element tennessine (Ts) have ever been identified.

The atomic number of tennessine is 117

01.3 Predict the number of outer shell electrons in an atom of tennessine.

Give one reason for your answer.

Use the periodic table.

[2 marks]

Number of outer shell electrons

Reason

01.4 Tennessine was first identified by a small group of scientists in 2010.

Suggest one reason why tennessine was not accepted as a new element by other

scientists until 2015.

[1 mark]

01.5 The discovery of isotopes explained why some relative atomic masses are not

whole numbers.

Element R has two isotopes.

Table 1 shows the mass numbers and percentage abundances of the isotopes of

element R.

Table 1

Mass number Percentage abundance (%)

67.6

7 92.4

Calculate the relative atomic mass (Ar) of element R.

Give your answer to 1 decimal place.

[3 marks]

Relative atomic mass (1 decimal place) =

Mark scheme

Show the mark scheme The mark scheme provides the answers for questions 01.1 through 01.5. It specifies that for 01.1, students must describe a ball of positive charge with embedded negative electrons. For 01.5, it shows the calculation steps for relative atomic mass: (6 * 7.6 + 7 * 92.4) / 100, resulting in 6.924, which rounds to 6.9.

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 a ball of positive charge do not accept references to 1 AO1

protons, nuclei, neutrons 4.1.1.3

with (negative) electrons 1

embedded

AO /

Spec. Ref.

01.2 (earliest) electrons 1 AO1

protons 4.1.1.3

(latest) neutrons

AO /

Spec. Ref.

01.3 AO2

(number of outer shell electrons) 4.1.2.1

71 4.1.2.6

(reason) (tennessine is in) allow the number of outer 1

Group 7 electrons is the same as the

group number

allow tennessine is a halogen

MP2 is dependent on MP1

being awarded

AO /

Spec. Ref.

01.4 (time needed for) peer review allow the idea that other 1 AO3

scientists had to check the 4.1.2.2

results – HEMISTRY – –

AO /

Spec. Ref.

01.5 (Ar =) AO2

4.1.1.6

(6 × 7.6) + (7 × 92.4) 45.6 + 646.8 1

allow

100 100

allow (6 × 0.076) + (7 × 0.924)

allow 0.456 + 6.468

= 6.924 1

= 6.9 allow an answer correctly 1

rounded to 1 decimal place from

an incorrect calculation which

uses all the data in the table

– HEMISTRY – –

Total Question 1 9

Question 2

How to answer it

Atomic Structure and the Periodic Table

What this question tests

This question assesses your ability to recall the history of the atom, use the Periodic Table to predict properties of unknown elements, understand the importance of peer review in science, and perform calculations for relative atomic mass (Aᵣ) using isotopic abundance.

Part 01.1

The Plum Pudding Model

💡 Key Knowledge

The Plum Pudding model was proposed by J.J. Thomson after he discovered the electron. It was the first model to suggest atoms weren't solid, indivisible spheres.

✅ Correct Answer

  • A ball of positive charge.
  • With (negative) electrons embedded in it.

❌ Common Errors

Do not mention protons, neutrons, or a nucleus. These were discovered later! If you use these terms, you will lose the marks for this specific model.

Part 01.2

Order of Discovery

🧠 Exam Technique

Think of the timeline of atomic models:

  1. Electrons (Plum Pudding)
  2. Protons (Nuclear model/Rutherford)
  3. Neutrons (Chadwick - the last to be found because they have no charge!)

✅ Correct Answer

Earliest: Electrons
Middle: Protons
Latest: Neutrons

Part 01.3

Predicting Properties (Tennessine)

💡 Key Knowledge

The Group Number in the Periodic Table tells you exactly how many electrons are in the outer shell of an atom.

✅ Correct Answer

Number: 7
Reason: It is in Group 7 (or it is a Halogen).

Examiner Note: You must get the number (7) correct to be awarded the mark for the reason. If you said "6" because it's in Group 6, you would get 0 marks.
Part 01.4

Scientific Process

🧠 Exam Technique

When a question asks why a discovery wasn't accepted immediately, the answer is almost always related to Peer Review. Other scientists must check the data to make sure it isn't a mistake.

✅ Correct Answer

To allow time for peer review OR so other scientists could verify/check the results.

Part 01.5

Calculating Relative Atomic Mass (Aᵣ)

📐 Step-by-Step Calculation

To find the average mass, we multiply each mass by its abundance, add them together, and divide by 100.

  1. Multiply: (6 × 7.6) + (7 × 92.4)
  2. Sum: 45.6 + 646.8 = 692.4
  3. Divide by 100: 692.4 ÷ 100 = 6.924
  4. Round to 1 decimal place: 6.9

✅ Final Answer

6.9

❌ Common Errors

  • Rounding: Students often forget the "1 decimal place" instruction. 6.92 or 7 will lose the final mark.
  • Calculator Slip: Ensure you use brackets on your calculator:
    ((6 × 7.6) + (7 × 92.4)) ÷ 100

Topics

Chemistry · C1: Atomic Structure and the Periodic Table

Question and mark scheme from the AQA GCSE Chemistry examination, Chemistry Paper 1 (Higher), 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.