Structure and Properties of Materials- 5.1 only

• An element is a pure substance that cannot be broken down into simpler substances
• A compound is a pure substance consisting of two or more elements chemically combined in either a covalent or ionic bond.
• Compounds can be broken down into its constituents by chemical reactions.

  • Thermal decomposition - exposing the compound to strong heat
  • Electrolysis - passing electric current through the compound
• Differences between Compounds and Mixtures.

  • Constituents of compounds are in fixed proportions whereas the constituents of mixtures are not.
• Mixtures are 2 or more elements or compounds which are physically combined