Metallic Bonding (Cambridge O Level Chemistry)

• Metal atoms are held together strongly by metallic bonding in a giant metallic lattice
• Within the metallic lattice, the atoms lose the electrons from their outer shell and become positively charged ions
• The outer electrons no longer belong to a particular metal atom and are said to be delocalised
• They move freely between the positive metal ions like a 'sea of electrons'
• Metallic bonds are strong and are a result of the electrostatic attraction between the positive metal ions and the negatively charged delocalised electrons

 

Diagram showing metallic lattice structure with delocalised electrons

• Metals conduct electricity
  • There are delocalised electrons that are free to move through the structure and carry charge
  • Electrons entering one end of the metal cause a delocalised electron to displace itself from the other end
  • Hence electrons can flow so electricity is conducted

• Metals are malleable and ductile
  • Layers of positive ions can slide over one another and take up different positions
  • Metallic bonding is not disrupted as the outer electrons do not belong to any particular metal atom so the delocalised electrons will move with them
  • Metallic bonds are thus not broken and as a result metals are strong but flexible
  • They can be hammered and bent into different shapes or drawn into wires without breaking