Give two limitations of the simple particle model.
- It shows no forces between particles.
- It shows particles as solid spheres, but atoms are mostly empty space.
Answer No forces between particles, and particles drawn as solid spheres
GCSE Combined Science revision · Chemistry: atoms, bonding and amounts
The idea
The simple particle model shows solids, liquids and gases as particles drawn as small, solid, inelastic spheres. Its limitations are that there are no forces shown between the particles, all particles are drawn as spheres, and the spheres are solid, whereas real atoms are mostly empty space. In reality, the strength of the forces between particles decides melting and boiling points.
- State what the model shows.
- List what it leaves out.
- Link the missing forces to changes of state.
Watch out The model shows how particles are arranged, but not why some substances melt at higher temperatures.
See it worked
Your turn
Which is a limitation of the particle model?
In the particle model, particles are represented as:
Explain why the particle model cannot explain why substances have different melting points.
Write your answer, then see a model answer
- Missing forces.
- Link to energy needed.
Answer It does not show the forces between particles, and the strength of those forces decides how much energy is needed to melt a substance.
In past papers
4 official questions in 4 papers since 2019. The latest:
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