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Dalton Model
John Dalton was a British chemist that published a book called New System of Chemical Philosophy. In his book, he explained that every element is made up of small atoms. He also explained that the masses of different elements are different. -
Thomson Model
In 1897, J.J. Thomson, a British scientist, proposed a new model of the atom. His model said that an atom is a sphere that is positively charged that has electrons embedded in it. He described his model as looking like a muffin with berries in it. -
Nagaoka Model
A new model of the atom was proposed by Japanese physicist Hantaro Nagaoka. This model said that there was a large shere with a positive in the center. Electrons revolved around the sphere as planets would around the sun. -
Rutherford Model
British Scientist Ernest Rutherford thought that the atom is mostly empty space. He said that the electrons orbit randomly arond the small nucleus that is positively charged. -
Bohr Model
Niels Bohr, a Danish physicist, determined that in fact, the electrons aren't just randomly orbiting around the nucleus. His new model showed that electrons moved in specific layers or shells. He said that atoms give off or absorb energy when the electrons move from one shell to another. -
Chadwick Model
The British physicist James Chadwick discovered the neutron. The neutron is a particle that is neither positively or negatively charged. He said that the atomic mass would be determined by the number of protons and neutrons in the atom. The neutrons as well as the protons were in the nucleus and the electrons revolved around the neucleus -
Modern Model
The modern model of the atom consists of a nucleus containing protons and neutrons. It also consists of an "electron cloud" that revolves around the nucleus. The electrons are all negatively charged. The atomic model has been this way since the 1920's.
