How is Thomson's model of an atom different from Dalton's model?

4.16 The dalton (symbol Da) is used as a name for the unified atomic mass unit. It is widely used by polymer chemists and biochemists (see footnote (c) in Table 7 of the current Brochure). The CCU acknowledged that the name Dalton has advantages over “unified atomic mass unit”: it is shorter and works better with prefixes. Menurut Dalton, atom merupakan partikel terkecil suatu materi yang berbentuk bola. Dalton menyatakan bahwa bola-bola atom tersebut khas untuk setiap unsurnya. Berdasarkan penggambaran atom sebagai bola pejal, maka model atom Dalton dikenal pula sebagai model atom bola pejal. Berikut beberapa poin dalam teori atom Dalton: 1). John Dalton’s atomic theory experiment was the first attempt to describe all matter by way of atoms and their properties in a way that was complete. His theory was based on two verified scientific laws: the law of conservation of mass and the law of constant composition.

1 Answer

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.

Explanation:

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.

John Dalton Atom

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