Describe the differences between the arrangement and movement of particles in a solid and in a gas.

Edexcel GCSE Chemistry (1CH0) — 2.1 States of matter · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

In a solid the particles are arranged in a regular, fixed pattern and can only vibrate about their fixed positions – they cannot move past one another.
In a gas the particles are far apart and move randomly in all directions, possessing the greatest kinetic energy of the states of matter.

Examiner tips

Use the word "regular" for solids and "far apart" for gases. Mention "vibrate" for solids and "move randomly" for gases. Show the contrast clearly in two separate sentences.

Common mistakes

Confusing the arrangement of particles in a gas as regular. Forgetting to state that solids cannot move past each other. Using vague terms like "close together" for gases.

Mark scheme (4 marks)

Particles in a solid are in a regular arrangement
Particles in a solid cannot move past each other / only vibrate about fixed positions
Particles in a gas are relatively spread out / far apart
Particles in a gas move randomly in all directions / have the most energy

Key terms in this question

solid · gas