Elements

• Element - A substance made up of atoms all having identical atomic structure
• Air is not pure, it includes : nitrogen, oxygen, argon and carbon dioxide
• Molecule - a cluster of atoms that are chemically bonded together.
• Compound - a substance made from two or more different elements that have been chemically joined. 
• Pure Substance - A substance with one type of atom/molecule throughout its structure. It may exist as an element or compound.
• Properties of a metal: 

  • High melting point 
  • Good conductor of heat and electricity 
  • Malleable  
  • Shiny  
• Properties of a non- metal: 

  • low melting point 
  • Bad conductor of heat and electricity 
  • Brittle  
  • Dull 

   
• A chemical reaction always forms one or more new substances 
• Thermal Decomposition – Using heat to break down a compound