When did John Dalton discover the atom?

John Dalton did not discover the atom, as it was discovered by Democritus during the Greek era. John Dalton proposed the atomic theory.

John Dalton was born in 1766 in England. At the age of 26, Dalton became a teacher of mathematics and philosophy at Manchester's New College. During the early 1800s he began to study the sciences and these studies led him to publish his atomic theory. The theory stated that all elements are made from atoms and atoms have different properties. He also theorized that atoms can not be artificially created. In 1826, his atomic theory won him the Society's Royal Medal.