Particle model

• What are the three states of matter?

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

  Melting point
• At what point do boiling and condensing occur?

  Boiling point
• How are particles represented in the simple particle model?

  By small solid spheres
• How are particles arranged in a solid?

  Close together and regularly arranged
• How are particles arranged in a liquid?

  Close together and randomly arranged
• How are particles arranged in a gas?

  Spread apart and randomly arranged
• What distinguishes a chemical change from a physical change?

  Chemical changes involve a chemical reaction
• What is required for a physical change to occur?

  Energy and a change in state
• What are examples of physical changes?

  Melting, boiling, freezing, condensing
• What is a limitation of the particle model?

  It does not account for forces of attraction
• What determines the amount of energy needed to change state?

  Strength of forces between particles
• What is the relationship between particle forces and melting/boiling points?

  Stronger forces mean higher melting/boiling points
• What does the nature of particles depend on?

  Type of bonding and substance structure
• What are the key features of the particle model in terms of states of matter?

  • Three states: solid, liquid, gas
  • Particles represented as small solid spheres
  • Solids: close together, regularly arranged
  • Liquids: close together, randomly arranged
  • Gases: spread apart, randomly arranged
• What are the differences between physical and chemical changes?

  • Physical changes: involve energy and state changes, no change in particles
  • Chemical changes: involve chemical reactions, change from reactants to products
• What are the limitations of the particle model?

  • Does not account for forces of attraction between particles
  • Does not account for the size of particles and the space between them
  • Does not consider the nature of particles (bonding and structure)