Choose Your Own Chemical Adventure

"Yes. Leucippus and his pupil Democritus both thought of matter as being made up of tiny indivisible particles which they named atomos. They argued that if it were possible to divide an object into ever smaller particles ad infinitum these particles would have to have zero size."

"I see. And this would mean that matter is made of nothing, which just doesn't make sense", you say.

"Very good. For this reason they said that there must exist a smallest particle - a kind of lower limit. Atoms must have non-zero size".