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 ...

Bohr began to work on the problem of the atom's structure. Ernest Rutherford had recently suggested the atom had a miniature, dense nucleus surrounded by a cloud of nearly weightless electrons.

This 'solar system' model of the atom is the way that most people think about atoms today. It is known as the Rutherford-Bohr model of atomic structure. The neutron was difficult to discover ...

Therefore, electrons cannot be arranged at random, but they must have fixed levels of energy within each type of atom. Bohr's 'solar system' model of the atom is the way that most people think ...

Niels Bohr adapted Ernest Rutherford's nuclear model. Bohr did calculations that led him to suggest that electrons orbit the nucleus in shells. The shells are at certain distances from the nucleus.

So convincing is this model that after only twelve years it is known no longer as “the atomic model of Rutherford and Bohr,” but is simply taken for granted as “the atom.” In this ...