AQA GCSE Chemistry Chemistry Paper 1 (Foundation), June 2024: Question 5

10 marks · Low Demand difficulty · Short Answer

Identify subatomic particles in a carbon-13 atom, determine the molecular formula of hexafluoroethane, and describe the structure and bonding of carbon allotropes including fullerenes, graphite, and diamond.

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Question

Question 5 contains eight parts about carbon and carbon compounds. Parts 05.1 to 05.3 show carbon represented with mass number 13 and atomic number 6, asking candidates to select the number of protons, neutrons, and electrons from options 1, 6, 7, and 13. Part 05.4 displays the chemical structure of C2F6 (two central carbons single-bonded together, each bonded to three fluorines) and asks to complete the formula C_F_. Part 05.5 asks for the reason for methane's low boiling point from three multiple-choice options. Part 05.6 asks for the shape of buckminsterfullerene (cubic, cylindrical, or spherical). Part 05.7 provides a diagram of layered graphite sheets and asks how many covalent bonds each carbon atom forms (1, 2, 3, or 4). Part 05.8 shows a 3D tetrahedral network diagram of diamond and asks to describe its structure and bonding for 3 marks.
Question text

05 This question is about carbon and carbon compounds.

An atom of carbon is represented as:

05.1 What is the number of protons in this atom of carbon?

Tick ( ) one box.

[1 mark]

16 7 13

05.2 What is the number of neutrons in this atom of carbon?

Tick ( ) one box.

[1 mark]

16 7 13

05.3 What is the number of electrons in this atom of carbon?

Tick ( ) one box.

[1 mark]

16 24 7 13

05.4 Figure 10 shows the structure of a carbon compound.

Figure 10

Complete the formula of the carbon compound.

*23* [1 mark]

C__ F__

05.5 Methane:

• is a carbon compound

• exists as small molecules

• has a low boiling point.

What is the reason for the low boiling point of methane?

[1 mark]

Tick ( ) one box.

Covalent bonds and intermolecular forces are weak.

Only covalent bonds are weak.

Only intermolecular forces are weak.25

05.6 Buckminsterfullerene (C60) is a form of carbon.

Buckminsterfullerene was the first fullerene to be discovered.

What is the shape of a buckminsterfullerene molecule?

[1 mark]

Tick ( ) one box.

Cubic

*24* Cylindrical

Spherical 26

05.7 Graphite is a form of carbon.

Figure 11 represents the structure of graphite.

Figure 11

How many covalent bonds does each carbon atom form in graphite?

[1 mark]

Tick ( ) one box.

*25* 2

4 27

05.8 Diamond is another form of carbon.

Figure 12 represents the structure of diamond.

Figure 12

Describe the structure and bonding in diamond.

[3 marks]

Mark scheme

Show the mark scheme Mark scheme for Question 5: 05.1 gives answer 6 (1 mark); 05.2 gives answer 7 (1 mark); 05.3 gives answer 6 (1 mark); 05.4 gives C2F6 (1 mark); 05.5 gives 'only intermolecular forces are weak' (1 mark); 05.6 gives 'spherical' (1 mark); 05.7 gives '3' (1 mark); 05.8 awards 1 mark for giant structure / lattice, 1 mark for covalent bonds, and 1 mark for each carbon forming four bonds (3 marks total). Question total is 10 marks.

Question 5

AO /

Question Answers Extra information Mark

Spec. Ref.

61 AO2

05.1

4.1.1.5

AO /

Spec. Ref.

71 AO2

05.2

4.1.1.5

AO /

Spec. Ref.

61 AO2

05.3

4.1.1.5

AO /

Spec. Ref.

05.4 C2F6 1 AO2

4.2.1.4

AO /

Spec. Ref.

05.5 only intermolecular forces are 1 AO1

weak 4.2.2.4

AO /

Spec. Ref.

05.6 spherical 1 AO1

– – – 4.2.3.3

AO /

Spec. Ref.

05.7 3 1 AO1

4.2.3.2

AO /

Spec. Ref.

05.8 giant structure allow lattice 1 AO1

4.2.3.1

(of atoms joined by) covalent 1

bonds

each carbon / atom forms four 1

bonds

Total Question 5 10

How to answer it

Carbon, Bonding, and Allotropes

📋 What this question tests

This question assesses fundamental GCSE Chemistry concepts across atomic structure, simple molecular bonding, and giant covalent allotropes of carbon:

  • Deducing subatomic particles (protons, neutrons, electrons) from nuclear isotopic symbols.
  • Writing molecular formulas from displayed structural diagrams.
  • Explaining physical properties of small molecules (weak intermolecular forces vs. strong covalent bonds).
  • Identifying the structural forms and bonding rules in allotropes of carbon (fullerenes, graphite, and diamond).
Parts 05.1, 05.2 & 05.3

Subatomic Particles in Carbon-13 (¹³₆C)

Atomic Number and Mass Number

✅ Correct Selections

  • 05.1 Number of protons: 6 [1 mark]
  • 05.2 Number of neutrons: 7 [1 mark]
  • 05.3 Number of electrons: 6 [1 mark]

📐 Step-by-Step Working

  1. Protons: Read bottom number (atomic number) = 6
  2. Neutrons: Top number (mass) − bottom number (atomic) = 13 − 6 = 7
  3. Electrons: In an uncharged neutral atom, electrons = protons = 6

💡 Key Knowledge

  • The atomic number (lower number) defines the element and equals the number of protons.
  • The mass number (top number) is the total count of protons + neutrons.
  • Carbon-13 is an isotope of carbon; its proton count remains 6, but it has one extra neutron compared to Carbon-12.

❌ Common Errors

  • Choosing 13 for protons or electrons by confusing mass number with atomic number.
  • Assuming carbon always has 6 neutrons (forgetting that this isotope is specified as Carbon-13).
Part 05.4

Molecular Formula of a Halocarbon

Counting Atoms in Displayed Structures

✅ Correct Answer

C₂F₆

Award 1 mark for the correct subscript numbers: 2 after C and 6 after F.

🧠 Exam Technique

Carefully count each individual chemical symbol shown in Figure 10:

  • There are 2 central C atoms: C₂
  • There are 6 surrounding F atoms (3 on each carbon): F₆
Part 05.5

Boiling Point of Methane (CH₄)

Small Molecules and Intermolecular Forces

✅ Correct Answer

Tick: "Only intermolecular forces are weak."

1 mark for identifying that only the intermolecular forces between molecules are weak.

💡 Key Knowledge

Methane is a small covalent molecule:

  • The covalent bonds inside the molecule (between C and H) are very strong.
  • The forces between separate molecules are weak intermolecular forces.
  • Boiling requires overcoming only these weak intermolecular forces, which needs very little thermal energy.

❌ Major Misconception Alert

A very frequent mistake at GCSE is thinking covalent bonds break when a simple substance melts or boils. Covalent bonds NEVER break when methane boils!

Parts 05.6 & 05.7

Allotropes of Carbon: Buckminsterfullerene & Graphite

✅ Correct Answers

  • 05.6 Shape of buckminsterfullerene (C₆₀): Tick Spherical [1 mark]
  • 05.7 Covalent bonds formed per carbon in graphite: Tick 3 [1 mark]

💡 Key Knowledge

  • Buckminsterfullerene (C₆₀): A spherical hollow cage resembling a football made of hexagonal and pentagonal rings. (Nanotubes are cylindrical fullerenes).
  • Graphite: Each carbon atom joins to 3 other carbon atoms in hexagonal layers, leaving one delocalised electron per atom (enabling graphite to conduct electricity).
Part 05.8

Structure and Bonding in Diamond

3-Mark Extended Recall

✅ Correct Answer / Marking Points

A full 3-mark response must state all three distinct structural facts:

  1. It has a giant structure (or giant lattice). [1 mark]
  2. Atoms are held together by covalent bonds. [1 mark]
  3. Each carbon atom forms four bonds. [1 mark]

🧠 Exam Technique: "Structure & Bonding" Questions

Whenever a GCSE exam question asks to "Describe the structure and bonding..." of diamond, graphite, or silicon dioxide, structure your answer to hit these points:

  • Structure type: State "giant covalent lattice".
  • Bond type: State "covalent bonds".
  • Connectivity: State exactly how many bonds each carbon atom forms (4 for diamond, 3 for graphite).

❌ Common Errors

  • Describing properties instead of structure (e.g. stating "it is very hard" or "it has a high melting point" gets 0 marks here).
  • Mixing up diamond and graphite by stating each carbon atom forms 3 bonds.
  • Mentioning "intermolecular forces" or "molecules" — diamond has no separate molecules.

Topics

Chemistry · C1: Atomic Structure and the Periodic Table · C2: Bonding, Structure and the Properties of Matter

Question and mark scheme from the AQA GCSE Chemistry examination, Chemistry Paper 1 (Foundation), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.