AQA GCSE Combined Science: Trilogy Chemistry Paper 1 (Foundation), 2022: Question 1

13 marks · Low Demand difficulty · Short Answer

Identify properties, atomic structure, and trends of Group 1 elements, including state changes and reactivity.

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Question

The image contains a multi-part exam question about Group 1 elements. It features a diagram of a lithium atom showing 3 protons, 4 neutrons, and 3 electrons; a flow chart of lithium changing from solid to liquid (Stage 1) and liquid to solid (Stage 2); a bar chart showing melting points of Group 1 elements (Lithium 180°C, Sodium 98°C, Rubidium 39°C, Caesium 28°C) with a gap for Potassium; and shell diagrams of sodium and potassium atoms. Questions ask for the name of Group 1, subatomic particle counts, ion charge, identifying physical changes, reading and plotting graph data, describing trends, and explaining reactivity.
Question text

01 This question is about Group 1 elements.

01.1 What are the Group 1 elements known as?

[1 mark]

Tick ( ) one box.

Alkali metals

Halogens

Noble gases

01.2 Figure 1 shows a lithium atom.

Figure 1

What is the number of electrons and neutrons in the atom of lithium?

[2 marks]

Number of electrons

Number of neutrons

01.3 What is the relative charge on a lithium ion?

[1 mark]

Tick ( ) one box.

+1 0 –13

01.4 Lithium is heated and then cooled in an experiment.

*02* Two physical changes happen in the experiment.

Draw one line from each stage to the physical change that happens in that stage.

[2 marks]

Stage Physical change

Boiling

Condensing

Stage 1

Dissolving

Stage 2

Freezing

4 Melting

Figure 2 represents the melting points of some Group 1 elements.

Figure 2

01.5 What is the melting point of caesium?

Use Figure 2.

[1 mark]

*04* Melting point = °C

01.6 The melting point of potassium is 63 °C

Draw a bar for the melting point of potassium on Figure 2.

[1 mark]

01.7 Describe the trend of the melting points of the Group 1 elements in Figure 2.

[3 marks]

01.8 The boiling point of sodium is 883 °C

What is the state of sodium at 150 °C?

Use Figure 2.

[1 mark]

Tick ( ) one box.

Gas

Liquid

Solid 6

01.9 Figure 3 represents the electronic structure of a sodium atom and of a

potassium atom.

*05* Figure 3

Complete the sentence.

Choose the answer from the box.

[1 mark]

gains an electron loses an electron shares an electron

Potassium is more reactive than sodium because potassium more

easily .

Mark scheme

Show the mark scheme The mark scheme lists the following answers: 01.1: alkali metals; 01.2: 3 electrons and 4 neutrons; 01.3: +1; 01.4: Stage 1 matches to melting, Stage 2 matches to freezing; 01.5: 28 (°C); 01.6: bar plotted at 63 °C; 01.7: melting point decreases down Group 1 and the differences get smaller; 01.8: liquid; 01.9: loses an electron. It provides specification references for each part, predominantly from sections 5.1.1, 5.1.2, and 5.2.2.

Question 1

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 alkali metals 1 AO1

5.1.2.5

AO /

Spec. Ref.

01.2 3 / three must be in this order 1 AO2

5.1.1.5

4 / four 1

AO /

Spec. Ref.

01.3 +1 1 AO2

5.1.1.4

AO /

Spec. Ref.

01.4 AO1

5.2.2.1

do not accept more than one line from a box on the left

AO /

Spec. Ref.

01.5 28 (°C) 1 AO2

5.1.2.5

AO /

Spec. Ref.

01.6 bar plotted at 63 °C allow a tolerance of ± ½ a small 1 AO3

square 5.1.2.5

AO /

Spec. Ref.

01.7 allow converse in terms of

increasing melting point

(melting point) decreases as go ignore boiling points 2 AO1

down Group 1

allow 1 mark for (melting point)

decreases

(and the) differences get smaller 1 AO3

or

initial drop is largest 5.1.2.5

AO /

Spec. Ref.

01.8 liquid 1 AO3

5.1.2.5

5.2.2.1

AO /

Spec. Ref.

01.9 loses an electron 1 AO1

5.1.1.7

5.1.2.1

5.1.2.5

Total Question 1 13

How to answer it

Group 1 Elements: Properties and Trends

What this question tests

This question assesses your knowledge of the Alkali Metals (Group 1). You need to recall their names, understand atomic structure (protons, neutrons, electrons), identify physical state changes, and interpret data from graphs to describe trends in melting points and reactivity.

Part 01.1 to 01.3

Atomic Structure & Identification

Correct Answers

  • 01.1: Alkali metals
  • 01.2: Electrons: 3 | Neutrons: 4
  • 01.3: +1

Key Knowledge

  • Group 1: Alkali Metals
  • Group 7: Halogens
  • Group 0: Noble Gases
  • Ions: Group 1 atoms lose 1 electron to get a full outer shell, leaving them with a +1 charge.

🧠 Exam Technique: Reading Diagrams

In 01.2, look at Figure 1. The electrons are the small 'x' marks on the shells (count them: 2 in the first, 1 in the second). The neutrons are the shaded circles in the nucleus (count them: 4). Don't confuse neutrons with the unshaded protons!

Part 01.4

Physical Changes

Lithium heating and cooling

Correct Matching

  • Stage 1 (Solid to Liquid): Melting
  • Stage 2 (Liquid to Solid): Freezing

❌ Common Errors

Students often mix up condensing (gas to liquid) with freezing. Always check the starting and ending states provided in the flow diagram.

Part 01.5 to 01.7

Data Skills: Melting Point Trends

📐 Step-by-Step: Reading the Graph

  1. Identify the scale: On the y-axis, there are 5 small squares between 0 and 20. This means 1 small square = 4°C.
  2. 01.5 Caesium: The bar reaches 2 small squares above 20.
    20 + (2 × 4) = 28°C .
  3. 01.6 Potassium: To draw 63°C, find 60, then go up nearly 1 full small square (64°C would be one full square).

🧠 Describing Trends (01.7)

To get all 3 marks for describing a trend, you must be specific:

  • Mark 1: State the main direction (Melting point decreases as you go down the group).
  • Mark 2: Use data to support (e.g., Lithium is 180°C while Caesium is 28°C).
  • Mark 3 (The "Top Level" mark): Describe the rate of change. Notice the "gap" between bars gets smaller as you go down. The differences get smaller.
Part 01.8 to 01.9

States of Matter & Reactivity

Correct Answers

  • 01.8: Liquid
  • 01.9: loses an electron

Key Knowledge: Reactivity

Potassium is more reactive than Sodium because its outer electron is further from the nucleus. This means there is less attraction, so it loses the electron more easily.

🧠 Determining State (01.8)

To find the state at 150°C:

  • Is 150°C higher than the Melting Point (98°C)? Yes (It has melted).
  • Is 150°C higher than the Boiling Point (883°C)? No (It hasn't turned to gas yet).
  • Therefore, it must be a liquid.

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), 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.