AS/A-level Chemistry: Metallic bonding

• 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

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

• 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.

• 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.