Dalton's Atomic Theory
John Dalton first provided the explanation for the laws of chemical combination, in 1809.
The essential postulates of this theory are given below:
- Matter is composed of atoms, which cannot be created or destroyed.
- All the atoms of one element are alike (i.e. they have the same size, shape and mass) but are different from those of any other element.
- In compounds, atoms combine together in the ratio of small whole numbers and are held together by chemical forces. The smallest entity of a compound is known as a molecule.