ATOMIC MODELS
ATOMIC MODEL Atomic theory is the scientific theory that matter is composed of particles called atoms. The definition of the word atom has changed over the years in response to scientific discoveries. Initially, it referred to a hypothetical situation in which these particles had an internal structure of their own and perhaps did not deserve to be called atoms, but renaming atoms would have been impractical by that point. Dalton's Atomic Theory First atomic model was developed by John Dalton. The important postulates of Daltons atomic theory are 1)Elements are made up of tiny indivisible particles called atoms. 2)Atoms can neither be created nor destroyed. 3)Atoms of a given element are identical in mass and chemical properties. 4)Atoms of different elements have masses and chemical properties. 5)Compounds are formed when atoms of different elements combined in a fixed ratio. Using this theory, Dalton rationalized the various laws of chemical combinations which w...