Question

what is j.j thomson model

Answer 1

Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces.

Answer 2

Thomson's atomic model was proposed in 1904 and was called the plum pudding model.It was introduced right after Thomson's 1897 discovery of the electron,then called corpuscles.He said that no matter where matter came from,it contained particles that were the same and are smaller than the atoms that matter is formed from.
This experiment said that the atom contained a nucleus which had a highly positive charge.