Maharishi kanad : According to maharishi kanad the atom is indivisible because it is a state at which no measurement can be attributed.

Smallest part of matter is known as Atom

In 19th century

Dalton’s atomic theory was given by Dalton in 1808

1. Matter consists of indivisible atoms.
2. All atoms of given elements are identical in properties and mass.
3. Atoms of different elements differ(to be different ) in mass.
4. Compounds are formed when atoms of different elements combine in a fixed ratio.
5. Atoms are neither created nor destroyed in a chemical reaction.