Most metals are pretty strong and hard. This strength makes them useful for making things which need to be strong. Most metals are dense , which means heavy for its size. This heaviness can be useful for things like a hammer which needs a lot of weight. Some metals are not so dense, such as aluminium, which has different uses.
Metals conduct electricity .
Metals will always allow electricity to flow through them. Even mercury will. This is why wires and plugs and everything else in a circuit must be made of a metal. Metals conduct heat energy . Metals will allow heat to pass through them.