Particle Theory of Matter
All matter is composed of tiny particles.
These particles interact with one another through collisions and vibrations.
These particles can be elements, molecules or compounds.
In different states the particles of the substance interact differently.
Particle Nature of Gases
The kinetic theory of gases is used to predict the physical properties of gases.
This model assumes that the particles in a gas are well spaced and move in random directions and random speeds.
The only way to change the direction or speed of a particle is for them to collide with one another.
This theory can explain gas pressure as it relates to the number of collisions between gas particles and the wall of the container.
Compressibility of gases is due to the large spacing between particles.
The particles of a liquid are much closer together compared to a gas.
They are still free to move and occupy new positions however; they are likely to collide with another particle over a short time.
The lack of space makes liquids almost incompressible.
Particle Nature of Solids
The particles are densely packed with only enough space to vibrate.
Particles can only occupy a fixed position.
Due to the fixed nature of the particles solids have a defined volume as well as a defined shape.