Ernest Rutherford had recently suggested the atom had a miniature, dense nucleus surrounded by a cloud of nearly weightless electrons. There were a few problems with the model, however.

Physics has a problem—their key models of quantum theory and the theory of relativity do not fit together. Now, Dr. Wolfgang Wieland from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) is ...

Photo: Niels Bohr's research notes for his new atomic theory Rutherford's find came from a very strange experience. Everyone at that time imagined the atom as a "plum pudding." That is ...

Rutherford made a series of discoveries about the nature of atoms and, working with colleagues Hans Geiger and Ernest Marsden, presented a planetary model of the atom in 1911. In it, he laid out ...

It also tells us that chlorine has 18 neutrons (35 - 17) and, as the number of electrons and protons are equal in a neutral atom, chlorine also has 17 electrons. The relative mass of a nucleus is ...