What are the postulates of J.J Thomson? What are his drawbacks?

Postulates of J.J Thomson:

(i) An atom consist of the positively charged sphere and electron are embedded in it.

(ii) The negative and positive charges are equal in magnitude so the atom as a whole is electrically neutral.

The drawback of J.J Thomson:

In the J.J. Thomson, plum pudding model no separation between electrons and protons as they are held together inside the atom which is not possible and led to instability of the atom but the atom exists stable.