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What is metallic bond in AS/A-level Chemistry?
- The forces of attraction between the central core of ions and the sea of delocalized electrons
- In a metallic lattice, outer shell electrons will repel each other.
- The repulsive forces between the outer shell electrons, in this structure are so great that the outer shell electrons become delocalized.
- DELOCALISED ELECTRONS- Not under the control of one specific nucleus. They are shared by many nuclei in structure- able to move freely
- LOCALISED ELECTRONS- Under the control of one specific nucleus (an example are inner shells)
- The MORE electron shells a metal has, the WEAKER the metallic bond
- The FEWER electron shells a metal has, the STRONGER the metallic bond
Melting point:
The strength of the metallic bond depends on:
- The more delocalized electrons, the stronger the bond and the higher the melting point
- The more closely packed the atoms are the stronger the bond is and the higher the melting point
- The electrons are free to move throughout the structure, but the positive ions remain where they are
- High temperatures are needed to break metallic bonds and dislodge ions from rigid positions in lattice
Conductivity:
- Solid and liquid metals conduct heat and electricity
- The delocalized electrons are free to move in the solid lattice.
- These electrons can act as charge carriers in the conduction of electricity or as energy conductors in the conduction of heat.
Malleable and Ductile:
- The delocalized electrons in the 'sea' of electrons in the metallic bond, enable the metal atoms or layers to slide past each other when a stress is applied.
This is the end of the topic!