Metallic BondingOxford AQA IGCSE Chemistry: Revision notes
Section 1
What is metallic bonding?
Metals consist of giant structures of atoms arranged in a regular pattern. In metallic bonding, the outer-shell electrons of each metal atom become delocalised — free to move throughout the whole structure — leaving behind a lattice of positive metal ions.
Section 2
What holds a metal structure together?
Metallic bonding is best pictured as a lattice of positive ions surrounded by a 'sea' of delocalised electrons:
- The positive metal ions are arranged in a regular, repeating pattern
- The delocalised electrons move freely between the ions, throughout the whole structure
- Strong electrostatic attractions between the positive ions and the delocalised (negative) electrons hold the metal together
Think of metallic bonding as a rack of positively charged balls (the metal ions) fixed in a pattern, sitting in a 'sea' of freely-moving negative electrons that glue them all together.
Section 3
How is metallic bonding different from ionic and covalent bonding?
| Bonding type | What happens to electrons |
|---|---|
| Ionic | Electrons transferred between atoms |
| Covalent | Electrons shared between atoms |
| Metallic | Electrons become delocalised across the whole structure |
All three types of bonding involve electrons in the highest occupied energy levels, but they behave very differently in each case.
Must Know
- Metals are giant structures of atoms arranged in a regular pattern
- Metallic bonding = a lattice of positive ions surrounded by delocalised electrons
- The delocalised electrons are free to move through the whole structure
- Strong electrostatic attractions between positive ions and delocalised electrons hold the metal together
- This is different from ionic (electron transfer) and covalent (electron sharing) bonding
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