Revision table Lustre: metals shiny; most non-metals dull (iodine is shiny). Hardness: many metals hard; sodium and gold are softer. Sulphur and coal are softer and brittle. Malleability: metals flatten into sheets. Non-metals break. Ductility: metals make wires. Non-metals do not. Sonority: metals ring; coal and wood give a dull sound. Heat: metal spoon becomes hot; wooden spoon does not. Electricity: aluminium foil, iron nail, copper wire — bulb glows. Sulphur, coal, dry wood, stone — bulb does not glow. Exception: mercury is a liquid metal; graphite conducts electricity.