How is Thomson's model of an atom different from Dalton's model?
John Dalton and JJ Thompson proposed very different models of the atom. Both of them were of utmost importance in the development of future of the atomic model.
John Dalton proposed that all matter is composed of very small things which he called atoms. This was not a completely new concept as the ancient Greeks (notably Democritus) had proposed that all matter is composed of small, indivisible (cannot be divided) objects. He thought atoms to be literally 'a tomos' meaning 'uncuttable'
Later JJ Thompson using his Cathode ray tube experimented and found out that atoms were made up of different charged particles. This he called the plum pudding model. The Plum Pudding Model is a model of atomic structure proposed by J.J. Thomson in the late 19th century.
Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. He therefore proposed that atoms have structure similar to a plum pudding, with tiny, negatively charged electrons embedded in a positively charged substrate. This was later shown to be incorrect.