Solution:
A piece of coal is a non-metal, generally broken into pieces by beating with a hammer.Non-metals are those materials which do not conduct electricity in their molten state. These also have properties like non-malleability, non-ductility, softness, etc. Ductility is the property by which metals can be transformed into thin sheets by hammering. Non-metals generally break down on applying force. Iron, aluminium and copper are all metals, while coal is a non-metal and breaks into pieces by hammering.