Answer:
The concept of the atom that Western scientists accepted in broad outline from the 1600s until about 1900 originated with Greek philosophers in the 5th century BCE. Their speculation about a hard, indivisible fundamental particle of nature was replaced slowly by a scientific theory supported by experiment and mathematical deduction. It was more than 2,000 years before modern physicists realized that the atom is indeed divisible and that it is not hard, solid, or immutable.