Non-metals are the elements which have greater tendency to accept electron.
Non-metals are non malleable; non ductile, dull in appearance, non-sonorous, poor or non-conductors of heat and electricity. Most of the non-metals are gases For example: H, N, O, F, Cl and VIIIA group non-metals are gases. Bromine (Br) is the only non-metal found in liquid state. Some nonmetals like S, P, Se, I are solids.
Non-metals form negative ions (anions) by gaining electrons. In this way, non-metals are electronegative in nature and form acidic oxides. The valency of some non-metals depends upon the number of electrons accepted by them. For example, valency of chlorine atom is 1, as it accepts only 1 electron in its outermost shell.
Important physical properties of non-metals are as follows:
Physical properties of non-metals change gradually but uniquely in a group of non-metals. Non-metals usually exist in all three physical states of matter. The non-metals at the top of the group are usually gases while others are either liquids or solids.
Solids non-metals are brittle (break easily).
Non-metals are bad conductors of heat and electricity (except graphite).
They are not shiny, they are dull except iodine (it is lustrous like metals).
They are generally soft (except diamond).
They have low melting and boiling points (except silicon, graphite and diamond).
They have low densities.
