elements, compounds and mixtures.

• What does each symbol in the periodic table represent?

  A different element
• What defines an element?

  All atoms are the same
• What is a compound?

  Two or more different elements chemically combined
• What does "fixed proportions" mean in a compound?

  Elements are combined in a specific ratio
• How do the properties of compounds compare to their constituent elements?

  Compounds usually have different properties
• What is required to separate a compound back into its elements?

  A chemical reaction
• What characterizes a mixture?

  Different elements or compounds not chemically combined
• How can mixtures be separated?

  Using physical separation techniques
• What is a molecule?

  Any elements chemically combined
• What is the key difference between molecules and compounds?

  Molecules can be same or different elements
• What are the definitions of element, compound, mixture, and molecule?

  • Element: All atoms are the same
  • Compound: Different elements chemically combined
  • Mixture: Different elements or compounds not chemically combined
  • Molecule: Any elements chemically combined
• What are some physical separation techniques for mixtures?

  • Filtration
  • Distillation
  • Crystallization
  • Chromatography