부산대학교 도서관

A history of the atom is presented. The earliest ideas about atoms go back to Democritus in the fifth century bc. These ideas were revived by John Dalton in the eighteenth century by treating the atom as a solid sphere. In the 1890s J. J. Thomson discovered the electron and presented a “plum pudding” model of the atom. A few years later, Ernest Rutherford discovered the nucleus. His model of the hydrogen atom was similar to a planetary system with a proton at the center and an electron circling around it. Bohr modified the Rutherford model by invoking a quantum condition. The final and correct picture of the atom emerged with the formulation of quantum mechanics in 1926, and is nothing short of mind-boggling. All the forces of nature are discussed that explain how a nucleus remains stable despite repulsive forces between protons inside the nucleus.