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

Science; States of matter; KS3 Year 7; The particle model of matter

1.	Solid
2.	Liquid
3.	Gas

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.

Science; States of matter; KS3 Year 7; The particle model of matter

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.