Dalton's Atomic Theory eparimant based 1All elemenits are composed of tiny indivisible particies callied atoms 21Atoms of the same element are ideritical Atorms of any one element are different from those of any other element John Dalton 760 1844) 3) Atoms of different elements combine in simple whole number ratios to form chemical compounds 4)In chemical reactions, atoms are combined, separated, or rearranged-but never changed into atoms of another element