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 Rutherfordís
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.