metallic bonding

• physical properties of metallic bonding:

  • high melting temperatures
  • good electrical conductivity
  • good thermal conductivity
  • malleability
  • ductility
• metals have low ionisation energies
• the electrical conductivity of a metal generally increases as the number of outer electrons increases
• metallic bonding is the electrostatic force of attraction between the nuclei of metal cations and delocalised electrons
• delocalised electrons are electrons that are not associated with any single atom or any single covalent bond
• metals have a giant lattice structure which require a lot of energy to break so melting temperatures are very high
• group 1 metals have lower melting temperatures
• group 2 metals have higher melting temperatures
• d-block metals have high melting temperatures because they have more delocalised electrons per ion
• the smaller the cation, the closer the delocalised electrons are to the nucleus of the cation. This results in an increase in the forces between the nuclei and the delocalised electrons, and so an increase in melting temperatures.
• when a potential difference is applied across the ends of a metal, the delocalised electrons will be attracted to the positive terminal.

  This movement of electrical charge constitutes an electrical current
• Thermal conductivity factors:

  • the free-moving delocalised electrons pass kinetic energy along the metal
  • the cations are closely packed and pass kinetic energy from one cation to another
• ductility- the ability for a metal to be stretched or drawn into a wire