The main postulates of Dalton’s Atomic theory are :
- Matter is made up of extremely small, indivisible particles called atoms.
- Atoms of the same substance are identical in all respects, i.e. they possess same size, shape, mass and chemical properties, etc.
- Atoms of the same substance are different in all respects, i.e. they possess different sizes, shapes, masses and chemical properties, etc.
- An atom is the smallest particle that takes part in chemical reactions.
- Atoms of different elements may combine with each other in a fixed, simple, whole number ratio to form compound atoms.
- Atoms can neither be created nor destroyed, i.e. atoms are indestructible.
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Shortcomings of Dalton’s Atomic theory :
- It failed to explain how atoms of different elements differ from each other since it did not throw any light on atomic structure.
- It could not explain how and why atoms of different elements combine with each other to form compounds – atoms or molecules.
- It failed to explain the nature of forces that bind together different atoms in a molecule.