Rutherford's experiment conflicted with Thomson's model because it showed that
A. the atom contains positively and negatively charged particles.
B. the atom is composed of mostly empty space.
C. the atom is full of a positively charged substance.
D. the atom contains a nucleus with protons and neutrons.

In his experiment, he took a gold foil and bombarded it with alpha particles (carrying positive charge). He thought that the particles will pass straight through the foil, but to his surprise, many of them passed through, some of them deflected their path and a few of them bounced back.

From this he concluded that in an atom, there exist a small positive charge in the center. Due to this positive charge, the alpha particles deflected their path and some of them bounced straight back their path. He also concluded that an atom consist of a lot of empty space.

J.J Thomson proposed a model known as plum pudding model. He considered atom to be a pudding of positive charge in which negative particles are embedded such as plum.

Thus, the correct answer is Option B.