The Particle Model

• What are the three states of matter?

  Solid, liquid, and gas
• At what point do melting and freezing occur?

  At the melting point
• At what point do boiling and condensing occur?

  At the boiling point
• How can the states of matter be represented in the particle model?


  • Particles are represented by small solid spheres.
  • In a solid, particles are close together and regularly arranged.
  • In a liquid, particles are close together but randomly arranged.
  • In a gas, particles are spread apart and randomly arranged.
• What is a chemical change?


  A change that requires a chemical reaction and produces different substances
• What is a physical change?


  A change that involves changes in state without altering the particles themselves
• What are examples of physical changes?


  Melting, boiling, freezing, and condensing
• What is a limitation of the particle model regarding changes of state?


  It does not account for the forces of attraction between particles
• How does the strength of forces between particles affect melting and boiling points?


  The stronger the forces, the higher the melting and boiling points
• What factors influence the nature of particles in a substance?


  The type of bonding and the structure of the substance
• What does the size of particles and the space between them affect?


  The nature of the particles involved in a substance