Section 1h: metallic crystals 1.45 describe a metal as a giant structure of positive ions surrounded by a sea of delocalised electrons 1.46 explain the malleability and electrical conductivity of a metal in terms of its structure and bonding Metallic crystals have a giant structure of positive ions surrounded by a ‘sea’ of delocalised electrons which can move around in the lattice as shown below. The bond between the metal ions is called a metallic bond. A metallic bond is the attraction between the positive metal ions and the delocalized electrons. (from http://www.bbc.co.uk/scotland/learning/bitesize/higher/chemistry/energy/bsp_rev3.shtml on 15/6/2010) This structure and bonding allows the following properties as shown by the table below. Property Explanation Metals are ductile (=can be pulled into wires) and malleable (= can be bent or hammered into different shapes without breaking); . The layers of positive metal ions can slide past each other without breaking the metallic bond; this is the case because there will always be delocalised electrons between these positive metal ions so the metallic bonds are still holding the metal ions together. Metals conduct electricity and heat well. Sea of delocalised electrons (they can move through the lattice) and carry the negative charge through lattice. Section 1g metallic crystals 1|Page