John Dalton provided a simple theory of matter to provide theoretical justification to the laws of chemical combinations in 1805. The basic postulates of the theory are:
1.All substances are made up of tiny, indivisible particles called atoms.
2. Atoms of the same element are identical in shape, size, mass and other properties.
3.Each element is composed of its own kind of atoms. Atoms of different elements are different in all respects.
4.Atoms combine with each other in simple whole number ratios to form compound atoms called molecules.
5. Atoms cannot be created, divided or destroyed during any chemical or physical change.