His atomic theory consisted of: Atoms make up all of matter, these atoms cannot be made or destroyed. This model was the earliest atomic model of a scientist. Democritus was the first person to use atom as a word. which was taken from the Greek word Atomos which means it cannot be broken down into simpler or smaller particles. He thought that these atoms were in a combination of hooks and and eye system but today it is stated that it is not true. He believed that atoms were a solid and indestructabe. His atom was a round solid circle.