C-REX rule: If the metal is above Carbon in the REactivity series, use Electrolysis eXtraction.
Cathode/Anode for aluminium electrolysis:
- CAthode — Al³⁺ ions gain electrons: CAthode = CAtions reduced
- ANODE — O²⁻ ions lose electrons → oxygen; the anode burns away (replaced regularly)
Bio = bacteria; Phyto = plants — "phyto" is from Greek for plant (same root as photosynthesis).
This memory aid covers Memory Aids within Extracting Metals for GCSE Chemistry. Revise Extracting Metals in Chemical Changes for GCSE Chemistry with 6 exam-style questions and 6 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 11 of 14 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
Practice questions for Extracting Metals
Which method is used to extract a metal that is MORE reactive than carbon?
Iron is extracted from haematite in a blast furnace. Describe how iron is obtained from iron oxide using carbon, and explain the term 'reduction' in this context.