21 September 2014

Physical and Chemical Properties of Non-Metals

Physical and Chemical Properties of Non-Metals : Science Ncert / Cbse Revision Notes

Sulphur, phosphorus, nitrogen, chlorine, iodine, boron, silicon, carbon, bromine, fluorine and oxygen are non-metals. Non-metals exist in all the three states. Silicon and carbon are solids; bromine is a liquid; chlorine, fluorine and oxygen are gases.

Physical Properties of Non-metals:

  • Non-metals are non-lustrous, non-malleable and not ductile, except for carbon fibres, which are ductile. Non-metals do not produce any sound when hit, which means they are not sonorous.
  • Non-metals do not conduct heat and electricity except for graphite.

Chemical Properties of Non-metals:

  • Non-metals react with oxygen and form acidic or neutral oxides. For example, sulphur reacts with oxygen to form sulphur dioxide, which is acidic. Carbon monoxide and nitric oxide are neutral oxides.
  • Generally, non-metals do not react with water though they may be very reactive in air. Such non-metals are stored in water. For example phosphorus is a very reactive non-metal. It catches fire if exposed to air. To prevent the contact of phosphorus with atmospheric oxygen, it is stored in water. 
  • Non-metals do not react with acids. 
  • The reaction of non-metals with bases is complex. For example, when chlorine reacts with a base like sodium hydroxide, it gives multiple products like sodium hypochlorite, sodium chloride and water.