compounds, Elements and Mixtures

• Elements


  Substances made entirely from atoms with the same atomic number
• Elements


  • Atoms may be bonded together into one giant structure (e.g. metals, carbon in diamond)
  • Atoms may bond together to make small molecules (e.g. oxygen)
• Elements that form diatomic molecules

  • Hydrogen
  • Oxygen
  • Nitrogen
  • Halogens
• Compounds


  Substances made of different types of atoms or ions chemically bonded in a fixed ratio
• Compounds


  • Atoms or ions may be bonded together in one giant structure (e.g. sodium chloride)
  • Atoms or ions may bond together to make small molecules (e.g. water)
• Mixture


  Substance composed of more than one element and/or compound which are physically mixed but not chemically combined
• what is a common Mixture?

  • Air
• Elements and compounds in air

  • Nitrogen (element)
  • Oxygen (element)
  • Argon (element)
  • Carbon dioxide (compound)
• Compounds have fixed ratios of atoms
• A compound is made up of two or more elements chemically bonded together.
• how are electrons arranged?

  in shells