The use of a metal follows from its properties. Aluminium has a low density, it is a good conductor of electricity, and a thin layer of aluminium oxide on its surface stops it corroding. That is why it is used for aircraft bodies, drinks cans and overhead power cables. Copper is an excellent conductor of electricity and heat, it is unreactive, and it is ductile, which means it can be drawn out into wires. So it is used for electrical wiring and water pipes. Gold is extremely unreactive, so it does not tarnish, and it is very malleable. It is used for jewellery and for electrical contacts in delicate electronics.
The reasoning also works backwards. If a job needs a light, strong, corrosion resistant metal, you look for a low density and a protective oxide layer. Pure metals are often too soft, so they are mixed to make alloys with more useful properties. Magnalium is aluminium mixed with magnesium. It keeps the low density but is stronger than pure aluminium, so it is used for aircraft parts. Brass is copper mixed with zinc. It is harder than copper but still resists corrosion, so it is used for taps, door handles and musical instruments.