(N/A) Thomson's experiments on electric discharge through gases demonstrated that atoms of all elements contain negatively charged particles,now known as electrons.
These electrons are identical for all atoms,regardless of the element.
Since atoms are electrically neutral,Thomson concluded that there must be an equal amount of positive charge present to balance the negative charge of the electrons.
To explain this,he proposed the 'Plum Pudding Model'.
According to this model,the positive charge of the atom is uniformly distributed throughout its entire volume.
Negatively charged electrons are embedded within this positive sphere,similar to seeds in a watermelon or plums in a pudding.