The particle model of matter
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Electricity
Waves
Forces and motion
Energy
Earth and atmosphere
Acids and alkalis
Chemical reactions
Pure and impure substances
The periodic table and properties of materials
Atoms, elements and compounds
States of matter
Genetics and evolution
Interactions and interdependencies
Plants
Human reproduction
Human gas exchange systems
Human nutrition, digestion and health
Human skeleton and muscles
Explainer Video
Summary
The particle model of matter
In a nutshell
Solids, liquids and gases all contain particles. Each state of matter will have a different particle arrangement, this will determine the properties seen for each state of matter.
Definitions
Key word | Definition |
| Particle model | The arrangement of particles in either solids, liquids or gases due to how much energy they hold. |
| Density | The number of particles per unit volume. |
| Diffusion | The movement of particles from an area of high concentration (lots of particles) to an area of low concentration (not a lot of particles). |
Particle model for solids, liquids and gases
particle property | solid | liquids | gases |
| Energy | Low energy | Medium energy | High energy |
| Attraction | Strong forces of attraction | Some forces of attraction | Very weak forces of attraction |
| Movement | Do not move - vibrate in fixed positions | Move past each other | Move quickly in random directions |
| Distance between particles | Fixed positions - next to each other | Close together | Large distances between particles |
| Density | High density | Medium density | Low density |
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How is the particle model related to properties?
Solids
- Particles do not move - solids have a fixed shape and volume.
- Particles are in fixed positions - solids cannot be easily compressed.
- Lots of particles in a small volume - solids are very dense.
Liquids
- Particles can move past each other - liquids do not have a fixed shape and can flow.
- Particles are packed closely together - liquids cannot be easily compressed.
- Quite a lot of particles in a small volume - liquids are quite dense.
Gases
- Particles move in random directions - gases do not have a fixed shape or volume.
- Particles have large spaces between them - gases can be compressed easily.
- Not many particles in a large volume - gases have low densities.
Example
Out of solids, liquids and gases which have the highest density arrangement of particles?
Solids - they contain high numbers of particles in a small volume.
Diffusion
Diffusion is the spreading out of particles, it is slow because particles will bump into air particles which slows down the movement and sends them in the wrong directions.
Example
When perfume is sprayed and the high volume of smell particles are spread out.
Smell particles (the red circles) are spreading out from the bottom left hand corner, where they are in high concentration, towards the air particles (the blue circles) where there is a low concentration of smell particles.
FAQs - Frequently Asked Questions
What is diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
Which type of particles have the least amount of energy?
Solid particles have the least amount of energy. The particles have low movement and are held closely together.
Why is the particle model used?
The particle model is used to explain the properties observed in solids, liquids and gases.
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