Limitations of Particle Model

• Physical changes — No new substances are made , but there is a change in the appearance. A physical change is usually reversible.

  Example : breaking, dissolving
• Chemical change: It produces new substances. The same types of atoms are arranged to make new bonds forming new chemicals. There are usually irreversible.

  Example: baking something , digesting food
• What does it mean by Limitations to the particle model?

  Means the properties that a diagram could not show you
• What are some limitations to the particle model?

  1. Forces between particles are missing.— This means it lacks to show how the particles attract or repel each other.
  2. Particles can be different sizes, not always the same sizes.
  3. Spaces between the particles is not always shown or accurate.
  4. Particles are 3D, not 2D.
  5. Movement of particles can be hard to show on paper.
• What is the exception to the general particle model?

  Water — It means water behaves differently compared to how we’d expect in simpler particle models.
• How is the particle arrangement of water different to what you already know?

  Solid water has an open structure.

  The particles are arranged in a regular pattern but the way they arrange leaves space between the particles.

  When water solidify it actually becomes less dense, this happens because of hydrogen bonding, forming a crystalline structure with more space between molecules.

  In contrast, most other substances become denser when they solidify