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Metallic Bonding [print-friendly version]
Found in pure metals and alloys e.g. Cu, Na, Zn, Ca, brass, bronze, steel
- Positively charged ions occupy fixed positions in a 3-D lattice. To form ions, the metal atoms release their valence electrons, 'free' electrons. These 'free' electrons are said to be delocalised.
- Metallic bonding is the strong electrical attraction between the 'sea' of delocalised electrons and the positive ions, which they surround.
- Structure - continuous lattice - the strong metallic bonding continues throughout the lattice uniformly.
- The overall charge is zero
- Explains physical properties
Property |
Explanation |
good electrical/thermal conductivity |
Mobile delocalised electrons are able to carry current through the metal and also transfer energy. |
density |
Ions are packed close together in the lattice |
high melting/boiling point |
A large amount of thermal energy is required to overcome the strong electrical attractions between the positive ions and the delocalised electrons. |
malleability/ductility |
Distortions do not disrupt the metallic bonding. layers can slide over each other. |
metallic lustre |
The external coating of 'free' electrons cause metals to be excellent light reflectors.
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