Chemistry J.J. Thomson of Cambridge University discovered the electron and soon after the French scientist Becquerel as well as the couple Pierre and Marie Curie investigated the phenomenon of radioactivity. In a series of pioneering scattering experiments Ernest Rutherford at the University of Manchester discovered the internal structure of the atom and the existence of the proton, classified and explained the different types of radioactivity and successfully transmuted the first element by bombarding nitrogen with alpha particles. His work on atomic structure was improved on by his students, the Danish physicist Niels Bohr and Henry Moseley. The electronic theory of chemical
Nuclear drip line 'dripped' out of the nucleus, hence giving rise to the term "drip line". Drip lines are defined for protons, neutrons, and alpha particles, and these all play important roles in nuclear physics. The nucleon drip lines are at the extreme of the proton-to-neutron ratio: at p:n ratios at or beyond the drip lines, no stable nuclei can exist. The location of the neutron drip line is not well known for most of the nuclear chart, whereas the proton and alpha drip lines have been measured for a wide range of elements. Nuclear stability is limited to those combinations of protons