The three states of matter are solid, liquid and gas
Melting and freezing take place at the melting point
Boiling and condensing take place at the boiling point
Particle representation
Particles are represented by small solid spheres
Solid
Particles are close together and regularly arranged
Liquid
Particles are close together but have a random arrangement
Gas
Particles are spread apart and have a random arrangement
Chemical change
Requires a chemical reaction, and for there to be a change from reactants to products
Physical change
Requires energy, and involves changes in state but there are no change to the particles themselves
Physical changes
Melting
Boiling
Freezing
Condensing
Limitations of the particle model
Does not take into account the forces of attraction between particles
Does not take into account the size of particles and the space between the particles
Forces of attraction between particles
The amount of energy needed to change state from solid to liquid and from liquid to gas depends on the strength of the forces between the particles of the substance
The stronger the forces between the particles the higher the melting point and boiling point of the substance
Nature of particles
The nature of the particles involved depends on the type of bonding and the structure of the substance (e.g. spaces between particles)
