October 21, 1998 Niels Bohr Niels Bohr was born in Copenhagen, he is the son of a physiology professor, and went to school at the University of Copenhagen, this is where he got his doctorate in 1911. Bohr won the Nobel piece prize for his theory of atomic structures. According to Microsoft Encarta His work drew on Rutherford? s nuclear model of the atom, in which the atom is seen as a compact nucleus surrounded by a swarm of much lighter electrons. He thought that electrons are arranged in definite shells, or quantum levels, at a big distance from the nucleus. The arrangement of these electrons is called the electron configuration. The number of these electrons equals the atomic number if the atom; hydrogen has a single electron, helium has 2, and uranium has 92.

The electron shells are built from a first shell to a total of seven shells. The first shell is complete with two electrons, the second can hold up to eight electrons, and the following shells hold larger numbers. The last electrons determine the chemical behavior of the atom.