Daltons Model of the Atom

Elements are composed of minute, indivisible particles called atoms. 

Atoms of the same element are alike in mass and size. 

Atoms of different elements have different masses and sizes. 

Chemical compounds are formed by the union of two or more atoms of different elements. 

Atoms combine to form compounds in simple numerical ratios, such as one to one, one to two, two to three, and so on. 

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Thomson had shown that atoms contain both negatively and positively charged particles. Clearly, the Dalton model of the atom was no longer acceptable. Atoms are not indivisible but are instead composed of smaller parts. Thomson proposed a new model of the atom. 

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