Metals also consist of a giant structure. Metallic bonds involve the all important free electrons which produce all the properties of metals. These delocalised electrons come from the outer shell of every metal atom in the structure. These electrons are free to move through the whole structure, so metals are good conductors of heat and electricity
These electrons also hold the atoms together in a regular structure. There are strong forces of electrostatic attraction between positive metal ions and the negative electrons. They also allow the layers of atoms to slide over each other, allowing metals to be bent and shaped.
Metallic Structures 2
Pure metals aren't quite right for certain jobs. So scientists mix two or more metals together - creating an alloy with properties they want.
Different elements have different sized atoms. So when another metal 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. So alloys are harder.