JJ THOMSON(1897)

He was the first scientist to show that the atom was made of even smaller things. He also proposed the existence of a (+) particle… His atomic model was known as the “raisin bun model”… 

In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged. In addition, he also studied positively charged particles in neon gas. Thomson realized that the accepted model of an atom did not account for negatively or positively charged particles. Therefore, he proposed a model of the atom which he likened to plum pudding. The negative electrons represented the raisins in the pudding and the dough contained the positive charge. Thomson's model of the atom did explain some of the electrical properties of the atom due to the electrons, but failed to recognize the positive charges in the atom as particles. 

Atoms are made mostly out of (+) charged material, like dough in a bun. The (-) charged electrons are found inside the (+) dough.