Chemical Formulas

• Positive ions can combine with negative ions to form ionic compound, using the crossover method
• mono - one atom

  di - two atoms

  tri - three atoms
• Ammonia - NH3

  Chlorine - Cl2
• compound ions / molecular ions

  Ions that have an extra electron or are missing an electron
• Ions with a name ending with ' ate ' tells us there is oxygen in the ion
• Half equations show how electrons are transferred during reactions. In half equations, e- stands for one electron