Giant metallic structures and alloys

• Metals form a giant lattice of positive metal ions in a sea of delocalised electrons
• The electrostatic attraction between the positive ions and the delocalised electrons is called a metallic bond. These metallic bonds are usually strong and need a lot of energy to overcome them, which is why most metals have high melting and boiling points
• The metallic bond operates in both pure metals and in alloys
• The layers of metal ions can slide over each other without disrupting the structure. This means that metals can be bent, shaped (they are malleable) and drawn into wires (they are ductile)
• The delocalised electrons can carry an electric current so metals are good electrical conductors both as solids and liquids
• Metals are also good heat or thermal conductors because the electrons can transfer the heat along the metal
• Alloys are mixtures of metals
• Introducing different-sized metal atoms into a metal lattice makes it harder for the layers to slide over each other so alloys are harder than pure metals