Dolton's Atomic Theory ---constitution of matter

 Some Basic  concepts of chemistry  #09

To watch video 

https://youtu.be/IR-2s_w6kEY

Postulates of Dolton's atomic theory :

• 1. Matter is composed of a large number of minute discrete particles Called Atoms
• 2. Atoms can neither be created nor be destroyed in a physical change or chemical reactions. 
• 3. Atoms of the same element are Identical with each other in mass, size,  shape, and other properties. 
• 4. Atoms  of different elements are different in all respects  i.e, they differ in mass, size, shape and properties. 
• 5. when atoms of different elements combine with  one another to form  a compound Atom ( later on called molecules),  they do so in simple whole number ratios.

Limitations of Dolton's Atomic theory:

1. Atom is no longer considered to be  indivisible.  It has now  been proved that an atom is composed of smaller particles like electrons, protons,  neutrons, positrons  etcetera. Also Modern discoveries proved that the atoms get divided during nuclear reactions. Thus, Atom is no longer the fundamental particle of matter and the Indivisibility of atom is no longer valid.
2.  As chemical reactions result either by sharing or transfer of electrons,  so Compound are no longer  accepted as to be formed by the union  of Atom.
3.  In sight of 3rd postulates, it can no longer be held correct with the discovery of isotopes.
4.  It could not give a clear distinction between  Atom and molecules. 

   yess, there is drawback of the Dolton's atomic 

theory.  but  it is very Important to study and understand. because this is the initiations of the concepts of ATOM.