Although the origin of idea that matter is composed of small indivisible particles called ‘α tomio’(which means – Indivisible) dates back to the time of Democritus, a Greek Philosopher. This idea of Indivisible particles again started emerging as a result of several experimental studies which led to laws of Chemical Combinations like Law of Conservation of Mass, Law of Definite Proportions etc.
In 1808, Dalton published a book titled “A New System Of Chemical Philosophy” in which he proposed the following: –
- Matter consists of individible atoms.
- All atoms of a given element have identical properties, including identical mass. Atoms of different elements differ in mass.
- Compounds are formed when atoms of different elements combine in a fixed ratio.
- Chemical reactions involved reorganisation of atoms. Atoms are neither created nor destroyed in a chemical reaction.
These are main kind of clauses of Dalton’s Atomic Theory.