When did democritus propose the idea of atoms? after 1900 a. d.before 500 b. c.about 430 a. d.about 430 b. c.

about 430 B.C.

Explanation:

Democritus is an ancient Greek philosopher that lived in the period between 460 BC and 370 BC. He had multiple theories, though some are hard to tell are they really from him or from his mentor. The one that most certainly came from him and from what he is actually known for is the idea of the atoms. Despite having no equipment to bale to study the matter properly, Democritus hypothesized that there are small things that make up everything, and named them atoms. He suggested that the atoms are very small, but indestructible. That there are infinite types, shapes, and sizes of atoms, and that they have small spaces between them. They have existed from the beginning of time and will exist forever. His idea actually turned out to be true, just that it took the humanity over 2,000 years to realize it.

they thoght they were going to nuke each other