Physical properties of non-metals
Hardness: Non-metals are not hard rather they are generally soft. But diamond is exception; it is most hard naturally occurring substance.
State: Non-metals may be solid, liquid or gas.
Lustre: Non-metals have dull appearance. Diamond and iodine are exceptions.
Sonority: Non-metals are not sonorous, i.e. they do not produce a typical sound no being hit.
Conduction: Non-metals are bad conductor of heat and electricity. Graphite which is allotrope of carbon is good conductor of electricity, and is an exception.
Malleability and ductility: Non-metals are brittle.
Melting and boiling point: Non-metals have generally low melting and boiling points.
Density: Most of the non-metals have low density.
Color: Non-metals are of many colors.