John Dalton's Atomic Theory

More than 2000 years ago, the Greek philosopher, democritus, stated that matter could not be divided into smaller and smaller pieces forever. Eventually the smallest piece of matter could be obtained. This idea was largely forgotten until the early 1800s. That's when English chemist John Dalton began observing the activities of weather by studying gases. Through his experiments and observations, Dalton developed the basic ideas of the atomic theory. Dalton concluded that pure substances called elements are made of extremely small particles called atoms. Each stated that atoms of the same element are exactly alike. And the atoms of different elements are different from one another. Dalton also stated that Adams could not be changed into different types of atoms by chemical reactions. He also theorized that compounds are formed by joining the atoms of two or more elements. These ideas served as the basis for what is known as the atomic theory.