For example, copper(II) sulfate contains Cu2+ ions.
The table shows the formulae of some common transition metal ions.
|Cations (positively charged)||Anions (negatively charged)|
|Ammonium NH4+||Hydroxide OH-|
The formulae of compounds containing polyatomic ions are worked out in a similar way to single atom ions. If more than one polyatomic ion is needed, its formula is written inside brackets.
Calcium hydroxide contains Ca2+ and OH- ions:
Deduce the formula for sodium carbonate.
Sodium carbonate contains Na+ and CO32- ions:
Deduce the formula for lead(II) nitrate.
Lead nitrate contains Pb2+ and NO3- ions:
The name of an ionic compound ends in:
|Name (-ide)||Formula||Name (-ate)||Formula|
|Calcium carbide||CaC2||Calcium carbonate||CaCO3|
|Potassium iodide||KI||Potassium iodate||KIO3|
|Iron(II) sulfide||FeS||Iron(II) sulfate||FeSO4|