Learning to Name and Write Formulas:

- Determining the type of compound you are working with.

- Applying the rules for naming or formula writing for that type of compound.

- Practicing until it becomes second nature.

How to Name Ions

You can tell that you have an ion when you see a postive (+) or negative (-) charge after the element or chemical compound. For example:

Mg2+,     F-,     CO32-,     Fe3+

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For Single Element Ions (e.g. K+ , Mg2+,  P3-)

  • To name positive (+) ions write the name as from the Periodic Table and add the word 'ion' afterwards.
  • To name negative (-) ions write the name from the Periodic Table but replace the ending with �ide�. Put the word 'ion' after the name.

For Single Element Ions of Transition Metals (e.g. Cu2+, Fe3+, Co3+

  • Write the ionic charge (the +1, +2 ...) as a Roman Numeral and put parentheses around the charge. So Cu2+ would be the Copper (II)ion.
  • While not transition metals, Pb, Sn should also have Roman Numerals with parentheses to show their charge..

For Polyatomic Ions (e.g. CO32-,  SO4-,  NH4+):