linguistic:paraphrasing
Thomson's model of the atom

The prevailing model of atomic structure before Rutherford's experiments was devised by J. J. Thomson. Thomson had discovered the electron through his work on cathode rays and between 1897 and 1904 he developed a model for atoms containing electrons arranged in concentric shells. To explain why atoms are electrically neutral, he proposed the existence of a commensurate amount of positive charge that balanced the negative charge of the electrons. Having no idea what the source of this positive charge was, he tentatively proposed that the positive charge was everywhere in the atom, adopting a spherical shape for simplicity. Thomson thought of the positive sphere as being akin to a liquid in that the electrons could move about in it, their arrangement and movements being determined by the balance of electrostatic forces.

Thomson was not quite satisfied with this simplistic idea and hoped to dispense with it as he refined his model. Thomson was never able to develop a complete and stable model that could predict any of the other known properties of the atom, such as emission spectra and valencies. The Japanese scientist Hantaro Nagaoka rejected Thomson's model on the grounds that opposing charges cannot penetrate each other. He proposed instead that electrons orbit the positive charge like the rings around Saturn. However this model was also known to be unstable.