Give various postulates of Dalton's atomic theory.

The main postulates of Dalton’s atomic theory (Dalton 1808) are:
1. Matter is made up of very small indivisible particles called atoms.
2. Atoms of the same element are identical in all respects.
3. Atoms of different elements differ in properties and mass.
4. Atoms combine in a simple but fixed ratio to form compound atoms (now called molecules).
5. Atom is the smallest particle which can take part in a chemical reaction.
6. Atom can neither be created nor destroyed during a chemical reaction.
7. Atoms of two elements may combine in different ratios to form more than one compound.