Metallic Bonding (CIE IGCSE Chemistry)

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• 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 attraction between the positive metal ions and the negatively charged delocalised electrons

 

Diagram showing metallic lattice structure with delocalised electrons

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• Metals have high melting and boiling points
  • There are many strong metallic bonds in giant metallic structures between the positive metal ion and delocalised electrons
  • A lot of heat energy is needed to break these bonds

• Metals conduct electricity
  • There are free electrons available 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