Metallic Bonding

Metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons. The organisation of the metal ions and the free-moving electrons give metals certain properties, such as malleability and ability to conduct heat and electricity.

 
 

Properties of metals and non-metals

Metals have certain properties which make them useful for things like frying pans, electrical power cables and car parts. In general, metals have a high melting point, conduct heat and electricity, have a high density and are malleable, which means they can be bent and hammered into shape without shattering. A brittle substance will break easily when bent. However there are a few exceptions:

  • Mercury is a metal and has a low boiling point so it exists as a liquid at room temperature

  • Graphite is a form of carbon, a non-metal, but can conduct electricity because it contains delocalised electrons

Structure of a metal

Metals consist of atoms arranged in neat rows or layers, stacked on top of one another. The outer electrons from each atom are able to abandon the nucleus and move freely throughout the metal - when this happens we say that the electrons are delocalised. Without the outer electrons spinning around the nucleus, each atom is now a positive ion. A metallic bond is the electrostatic attraction between a positive metal ion and the delocalised electrons.

 
 

The structure of a metal explains two important properties:

  1. Good conductors of electricity - remember that anything that is charged and free to move can conduct electricity. The delocalised electrons fit this criteria and it’s this that makes metals such good conductors.

  2. Malleable - a metallic lattice consists of layers that can slide over each other. This allows metals to be hammered or rolled into flat sheets without breaking.

teaparty.jpg

Did you know..

Mercury, the only metal which exists in a liquid form at room temperature, is responsible for a neurological condition caused by mercury poisoning. The condition, called erethism or ‘mad hatters disease’ was common among English hat makers who inhaled mercury vapours while they were processing animal furs.

Download worksheet: Metallic Bonding / Answers Next Page: Electrolysis