Metallic Bonding (SQA National 5 Chemistry): Revision Note

Metallic bonding & conductivity

• Metallic bonding is the force of attraction that holds the atoms together in a metallic element

  • It is found in all metals and alloys

• A metallic bond is the strong electrostatic force of attraction between the positively charged ions and the delocalised electrons

Metallic bonding

Sea of delocalised electrons

• Metal atoms have a weak hold on their outer shell electrons

• In a metallic structure, these outer electrons are lost from the atoms and become delocalised

  • These are electrons that are no longer associated with any single atom

  • They are free to move throughout the entire metal structure

  • When the atoms lose these electrons, they become positively charged ions

• These positive ions are arranged in a regular, repeating pattern, forming a giant lattice

  • The delocalised electrons flow around and between these positive ions, like a "sea" of electrons

Electrical conductivity

• The unique structure of metals explains their properties

  • The most important one to explain is electrical conductivity

• Metals are excellent conductors of electricity in both the solid and liquid states

• To conduct electricity, a substance needs charged particles that are free to move

• Metals contain delocalised electrons

• These electrons are free to move throughout the metallic lattice

• When a voltage is applied, the delocalised electrons are forced to move towards the positive terminal, creating a flow of charge, which is an electric current