1.1. The particle model

The three states of matter are solid, liquid, and gas.

At the melting point, melting and freezing take place.

In a solid, particles are close together and regularly arranged. In a liquid, particles are close together but have a random arrangement. In a gas, particles are spread apart and have a random arrangement.

Chemical changes require a chemical reaction and result in products that are chemically different from the reactants. Physical changes involve changes in state (like melting, boiling, freezing, condensing) but do not change the particles themselves.

The limitations include:

1. Forces of Attraction:

   • The model does not account for the forces of attraction between particles.
   • The energy required to change state (solid to liquid, liquid to gas) depends on the strength of these forces.
   • Stronger forces result in higher melting and boiling points.

2. Particle Size and Spacing:

   • The model overlooks the size of particles and the space between them.
   • The nature of the particles and their arrangement is influenced by the type of bonding and structure of the substance, affecting the spaces between particles.