Contrast aluminum and nitrogen. Show why aluminum is a metal and nitrogen is not.

Nitrogen: Non - metal = they are poor conductors of heat and electricity, they are brittle solids, not ductile in their solid state - they cannot be rolled into wires or pounded into sheets. They are usually dull and therefore show no metallic luster and they do not reflect light. They also have a low density.

Aluminium: Metal = Offers a rare combination of valuable properties. It is one of the lightest metals in the world: it's almost three times lighter than iron but it's also very strong, extremely flexible and corrosion resistant because its surface is always covered in an extremely thin and yet very strong layer of oxide film. It doesn't magnetise, it's a great electricity conductor and forms alloys with practically all other metals.