What Is the Solid Sphere Model As Proposed by John Dalton?

The solid sphere model proposed by John Dalton stated that atoms consisted of negative charges embedded in a solid continuum of positive charge. The magnitude of the embedded negative charge would cancel the positive charge of the continuum, rendering the entire atom neutral.

The Dalton model was put forward in 1803 and hypothesized that all elements are made of indivisible solid spheres of atoms. The model was one of the first to propose that atoms of the same element are identical, that all atoms of one element are indistinguishable from all other atoms of this element. The model also accurately described compounds as fixed ratios of the atoms of different combined elements. Although the model proposed that chemical reactions result from the combination or separation of atoms, it did not explain how these chemical reactions could occur. The model also proposed that atoms of one element are never changed into atoms of another element, which is untrue.

To organize the elements, Dalton created a table of atomic weights, a precursor to the modern periodic table. Elements were organized based on their atomic weights relative to the weight of a hydrogen atom, which he assigned an atomic number of one, a practice that the modern table also adopted.