1.) All metals are hard, except sodium which can be cut with a knife.
2.) All metals have high melting point except mercury which melts in hand.
3.) All metals have high ignition temperature, except sodium and pottasium which burn in contact with air.
1.) All non metals are bad conductors of electricity, except graphite.
2.) All non metals are brittle/soft, except diamond.
3.) All non metals are non lustrous, except iodine.