Metals as Conductors (AQA GCSE Chemistry: Combined Science)

• 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

There is attraction between positive metal ions and delocalised electron

• 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