Metals as Conductors (AQA GCSE Combined Science: Trilogy): Revision Note Exam code: 8464

Metals as Conductors (AQA GCSE Combined Science: Trilogy): Revision Note

Exam code: 8464

How do metals conduct electricity?

  • Metals consist of giant structures

  • Within the metal lattice, the atoms lose their outer electrons and become positively charged metal ions

    • The outer electrons no longer belong to any specific metal atom and are said to be delocalised

  • Metals can conduct electricity because the delocalised electrons are able to move through the structure and carry a charge 

  • The metallic bond is the strong force of attraction between the positive metal ions and the delocalised electrons

  • This type of bonding occurs in metals and metal alloys, which are mixtures of metal

Diagram to show metallic bonding

metallic-bonding-update

There is attraction between positive metal ions and delocalised electron

Examiner Tips and Tricks

When explaining why metals conduct electricity in an exam, be careful that you don't write electrons move 'throughout' the structure, but say 'through' the structure.

How do metals conduct heat?

  • Metals are also good conductors of heat

  • The delocalised electrons are free to move and transfer thermal energy through the structure

  • Some metals are better conductors of heat energy than others

Table of different conductivities of metals

Metal

Thermal conductivity*

Silver

406

Copper

385

Gold

314

Brass

109

Aluminium

205

Iron

79.5

Steel

50.2

Lead 

34.7

*W/mK = Watts per metre Kelvin is a unit of thermal conductivity


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