All the objects around you, this device, your pen or pencil and things of nature such as rocks, water and plant constitute the matter of the universe. Matter is any substance which occupies space and has mass. Dalton, in 1808, proposed that matter was made up of extremely small, indivisible particles called atoms. (In Greek atom means which cannot be cut). This concept was accepted for number of years. The main postulates of Dalton’s atomic theory are · Matter is made up of small indivisible particles, called atoms. · Atoms can neither be created nor destroyed. This means that a chemical reaction is just a simple rearrangement of atoms and the same number of atoms must be present before and after the reaction. · Atom is the smallest particle of an element which takes part in a chemical reaction. · Atoms of the same element are identical in all respects especially, size, shape and mass. · Atoms of different elements...
