PH 122 Chapter Notes - Chapter 42: Nuclear Magnetic Moment, Electronvolt, Radionuclide
Document Summary
During the rst years of the twentieth century the only fact that researchers knew about the atom structure was that it contained electrons. Laboratory observations have spread the belief that since an atom is electrically neutral, it contained positive charges that balance the negative charge of the electrons. The atom model assumed that both positive and negative charges were uniformly distributed in a sphere. In 1911 ernest rutherford proposed an atom model where all positive charges where concentrated at the center of the atom, forming a nucleus, which in addition was responsi- ble for most of the mass of the atom. Physicists have measured quantities that characterize the nucleus of most elements. Stability: corresponds to the ability of an atom to ra- diate particles from its nucleus. An element that radi- ates is unstable, while that someone who does not is an stable element. A periodic table of nuclear properties or nuclidic chart contains an element and its isotopes.
