Answer: subatomic particles: negative charges (electrons) distributed in a mass of positive charge.
Step-by-step explanation:
1) John Dalton's model depicted the matter as the combination of tiny, indivisible particles, called atoms.
According to this model, atoms can not be created, destroyed, or divided into smaller particles.
2) When it was discovered that all forms of matter contained negative particles, by multiple experiments with cathode ray tubes, those particles where named electrons.
3) J.J. Thompson could determine that the mass of those negative charges was much smaller that the mass of the smallest atom (hydrogen). Concluding that existed smaller particles than the atom. Hence, Dalton's model was wrong: atoms was divisible into smaller subatomic particles.
4) Then J.J Thompson proposed the plum pudding model, in which the electrons (plums) are embeded into a uniform positive mass (pudding).