Diamond = 4 bonds = hard, Graphite = 3 bonds + 1 free = conducts + slides:
- Diamond: 4 bonds used → ALL electrons locked → NO conduction, VERY HARD
- Graphite: 3 bonds used → 1 electron free per C → CONDUCTS, soft layers SLIDE
Uses memory trick: "Diamond CUTS, Graphite WRITES" — diamond's hardness makes it ideal for cutting tools and drill bits; graphite's layered structure means layers rub off onto paper in pencils.
Allotropes: "ALL-otropes = ALL the same element, different structures" — diamond, graphite, graphene, fullerenes are all made entirely of carbon atoms arranged differently.
This memory aid covers Memory Aids within Giant Covalent Structures for GCSE Chemistry. Revise Giant Covalent Structures in Bonding & Structure for GCSE Chemistry with 21 exam-style questions and 21 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 12 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 Giant Covalent Structures
Why do giant covalent structures have very high melting points?
Explain why graphite conducts electricity but diamond does not.