Dalton's atomic theory

Almost after two millennia, the works on the simplifying matter was materialized by Dalton. In 1808 John Dalton postulated the famous Dalton’s Atomic Theory. He published this theory in a paper titled “A New Chemical Philosophy”; indeed the philosophy was new for that era. The postulates of Dalton’s Atomic Theory were as follows:

1. Matter is made up of indivisible particles known as atoms.
2. The properties of all the atoms of a given element are same including mass. This can also be stated as, all the atoms of an element have identical mass; atoms of different elements have different masses.
3. Atoms of different elements combine in fixed ratios to form compounds.
4. Atoms are neither created nor destroyed. This implies that during chemical reactions, no atoms are created nor destroyed. The formation of new products (compounds) results from the rearrangement of existing atoms (reactants).

Dalton’s Atomic Theory also suggested that the smallest part of an atom that can take part in a chemical reaction is an atom. Some postulates of this theory remain valid even in modern chemical thoughts. The atomic structure model proposed by Dalton has proved to be a stepping stone in chemistry and forms the base for modern atomic theories and quantum mechanics.