Edexcel IAL Chemistry AS 8.4 Formulae from oxidation numbers
Edexcel IAL Chemistry AS 8.4 Formulae from oxidation numbers
Write each ion with its charge, choose the smallest whole-number ratio that gives zero overall charge and preserve polyatomic ions with brackets where needed.
How this is tested
- Combine cation and anion charges in the smallest ratio to produce a neutral formula.
- Deduce double-salt formulae while preserving sulfate or other polyatomic-ion units.