"atomic theory." YourDictionary, n.d. Web. 12 October 2018. <http://www.yourdictionary.com/atomic-theory>.
atomic theory. (n.d.). Retrieved October 12th, 2018, from http://www.yourdictionary.com/atomic-theory
The physical theory of the composition of matter stating that common materials are composed of molecules, which are composed of atoms, which are composed of nuclei and electrons. It holds that the properties of composite entities, such as their structure and behavior, arise from the properties of their components.