Particle model

• All matter is made up of particles
• The behaviour of matter can be explain in terms of how the particles move and the forces between them
• The particles of a substance in each state are the same - only the arrangement and energy of the particles are different
• Solids

  • Strong forces of attraction hold the particles together
  • the particles are close together in a fixed, regular arrangement
  • the particles don’t have much energy so they can only vibrate in their fixed positions
• Liquids

  • weaker forces of attraction between the particles
  • the particles are close together but can move past each other and form irregular arrangements
  • these particles have more energy than the particles in a solid
  • the particles move in random directions at low speeds
• Gases

  • almost no forces of attraction between the particles
  • the particles have more energy than in liquids and solid
  • the particles are free to move and are constantly moving with random directions and speeds