AQA GCSE Combined Science: Trilogy Chemistry Paper 1 (Foundation), 2020: Question 4

8 marks · Standard Demand difficulty · Short Answer

Answer questions about the proportion, properties and structure of sodium chloride and metals in the periodic table, including balancing an equation and explaining conductivity.

Practise this question

Question

The page shows question 04 about elements and compounds with four parts. Part 04.1 includes Figure 5, a pie chart showing the proportion of elements in the periodic table that are metals and non-metals, with the non-metals shown as a smaller sector and dashed radial guides across the circle; the question asks for the percentage of elements that are metals and gives a blank line for the answer. Part 04.2 asks for two physical properties of metals with two numbered answer lines. Part 04.3 shows the equation Na + Cl2 → NaCl and asks the student to balance it; below is Figure 6, a labelled diagram of the sodium chloride lattice with alternating plus and minus ions. Part 04.4 asks what holds the particles together in sodium chloride and provides three tick-box options: electrostatic attractions, intermolecular forces, and metallic bonds. Part 04.5 says solid sodium chloride does not conduct electricity and asks for two ways to make it conduct electricity, with two answer lines.
Question text

04 This question is about elements and compounds.

04.1 Figure 5 shows the proportion of elements in the periodic table that are metals

and non-metals.

Figure 5

Determine the percentage of the elements in Figure 5 that are metals.

[2 marks]

Percentage = %

04.2 Give two physical properties of metals.

[2 marks]

04.3 Sodium reacts with chlorine to produce sodium chloride.

Balance the equation for the reaction.

[1 mark]

Na 14Cl → NaCl

+ 2

Figure 6 shows part of the structure of sodium chloride (NaCl).

Figure 6

04.4 What holds the particles together in sodium chloride?

Use Figure 6.

[1 mark]

Tick ( ) one box.

Electrostatic attractions

Intermolecular forces

Metallic bonds

04.5 Solid sodium chloride does not conduct electricity.

Give two ways in which sodium chloride can be made to conduct electricity.

[2 marks]

Mark scheme

Show the mark scheme The mark scheme shows that 04.1 is worth 2 marks: the metals sector is 8/10 of the circle, so 0.8 × 100 = 80%, with 20% also allowed if no other mark is awarded. For 04.2 it accepts any two physical properties of metals such as conducts electricity, conducts thermal energy, ductile, high melting point, malleable, shiny, strong, with conduct heat, high boiling point, can be bent/shaped, dense, and sonorous also allowed. For 04.3 the balanced equation is 2Na + Cl2 → 2NaCl, allowing multiples. For 04.4 the correct answer is electrostatic attractions. For 04.5 it accepts heating sodium chloride until molten/liquid and dissolving in water or forming an aqueous solution, or adding water, for a total of 8 marks.

AO /

Question Answers Extra information Mark

Spec. Ref.

04.1 8

× 100 or 0.8 × 100 1 AO2

5.1.2.3

= 80 (%) 1

if no other mark awarded allow 1

mark for 20 (%)

04.2 any two from: 2 AO1

5.1.2.3

• conducts electricity

• conducts thermal energy allow conducts heat

• ductile

• high melting point allow high boiling point

• malleable allow can be bent / shaped

• shiny

• strong

allow dense

allow sonorous

ignore chemical properties

04.3 2 Na + Cl2 → 2 NaCl allow multiples 1 AO2

5.1.2.5

5.1.2.6

5.3.1.1

04.4 electrostatic attractions 1 AO3

5.2.1.3

5.2.2.3

04.5 (heat sodium chloride until) 1 AO1

molten / liquid 5.2.2.3

dissolve in water allow form aqueous solution 1

allow add water

Total 8

How to answer it

Standard Demand

Elements, Compounds, and Bonding

What this question tests:

This question assesses your ability to interpret data from diagrams, recall physical properties of metals, balance simple chemical equations, identify ionic bonding, and understand the conditions required for ionic substances to conduct electricity.

Question 04.1: Interpreting Pie Charts

Calculation Steps

  1. Count the total number of segments in the pie chart: 10.
  2. Count the number of segments representing metals: 8.
  3. Calculate the fraction: 8/10 = 0.8.
  4. Convert to a percentage: 0.8 × 100 = 80%.
✅ Answer: 80%

Question 04.2: Physical Properties of Metals

💡 Key Knowledge: Metals have specific physical properties due to their giant metallic structure and delocalised electrons.
  • Conducts electricity or thermal energy.
  • Malleable (can be hammered into shape) or ductile (can be drawn into wires).
  • High melting/boiling points.
  • Shiny (lustrous) or strong.
🧠 Exam Technique: You only need to provide two. Do not list chemical properties (like "reacts with acid") as these will not be credited.

Question 04.3: Balancing Equations

✅ Answer: 2Na + Cl₂ → 2NaCl
❌ Common Errors: Forgetting to balance the chlorine atoms. Always check that the number of atoms of each element is the same on both sides of the arrow.

Question 04.4: Ionic Bonding

✅ Answer: Electrostatic attractions
💡 Key Knowledge: Sodium chloride is an ionic compound. It consists of a lattice of oppositely charged ions (Na⁺ and Cl⁻). The strong force of attraction between these opposite charges is called an electrostatic attraction.

Question 04.5: Conductivity of Ionic Compounds

💡 Key Knowledge: Ionic compounds only conduct electricity when the ions are free to move. In a solid, ions are locked in a fixed lattice.

To make them move, you must either:

  • Melt it: Heat the solid until it becomes a liquid (molten).
  • Dissolve it: Add it to water to form an aqueous solution.
🧠 Exam Technique: Be specific. Don't just say "add water"—say "dissolve in water" to show you understand the ions are being separated from the lattice.

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 Combined Science: Trilogy examination, Chemistry Paper 1 (Foundation), 2020. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.