PH 122 Lecture Notes - New Zealand, Atomic Number, Photon
Document Summary
The forces holding together the nucleus are large. Certain nuclei fall apart and emit ionizing radiation as they do. They can cause illness, but they can cure or diagnose as well. A classical particle of mass m bounces back and forth between two boundaries. Matter waves moving in opposite directions create standing waves. Only certain wavelengths meet the boundary conditions, so only certain energies are allowed. Confining neutrons and protons in the box of the nucleus means that their allowed energies are enormous. Number of protons determines the element, number of neutrons the isotope. Most elements have more than one stable isotope. Never acceptable: using atomic weights from the periodic table. For light nuclei, neutron and proton energy levels are about the same. As elements increase in size, more neutrons needed to keep nucleus stable. Eventually the nucleus cannot hold together, coulomb repulsion too strong. Ejected electrons cause a chain reaction of ionization of neon/argon gas.
