Metallic Bonding

• Metallic bonding involves delocalised electrons
• Metals also consist of a giant structure
• The electrons in the outer shell of the metal atoms are delocalised. There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons
• Electrostatic forces of attraction hold the atoms together in a regular structure and are known as metallic bonding. Metallic bonding is very strong
• Substances that are held together by metallic bonding include metallic elements and alloys
• It's the delocalised electrons in the metallic bonds which produce all the properties of metals
• Most metals are solid at room temperature
• The electrostatic forces between the metal atoms and the delocalised sea of electrons are very strong, so need lots of energy to be broken
• Most compounds with metallic bonds have very high melting and boiling points, so they're generally solid at room temperature
• Metals are good conductors of electricity and heat
• The delocalised electrons carry electric charge and thermal energy through the whole structure, so metals are good conductors of electricity and heat
• Most metals are malleable
• The layers of atoms in a metal can slide over each other, making metals malleable - this means that they can be bent, hammered or roled into flat sheets

  
• Alloys are harder than pure metals
• Pure metals often aren't quite right for certain jobs - they're often too soft when they're pure so are mixed with other metals to make them harder
• Most of the metals we use everyday are alloys - a mixture of 2 or more metals or a metal and another element. Alloys are harder and so more useful than pure metals
• Different elements ahve different sized atoms. So when another element is mixed with a pure metal, the new metal atoms will distort the layers of metal atoms, making it more difficult for them to slide over each other. This makes alloys harder than pure metals