| A | B |
|---|
| Democritus | philosophical atomism |
| John Dalton | first experimental model of atom |
| Alessandro Volta | invention of electical battery |
| J. J. Thompson | discovery of electron, plum pudding model of atom |
| Wilhelm Roentgen | discovery of x-rays |
| Ernest Rutherford | discovery of nucleus |
| Hans Geiger | gold foil experiment |
| Gustav Kirchoff and Robert Bunsen | developed prism spectroscope |
| James Chadwick | discovered neutron |
| Niels Bohr | quantized energy/planetary model of atom |
| Louise de Broglie | particles behave like waves |
| Werner Heisenberg | uncertainty principle - impossible to know both energy or momentum and exact position of an electron at the same time |
| quantum numbers | solutions to wave equations |
| principle quantum number (n) | energy level (1,2,3,4,5,6,7) |
| azimuthal quantum number (l) | sublevel (0 - n-1) (s, p, d, f) |
| magnetic quantum number (m) | orbital (0 - ±l) |
| electron-spin quantum number (m_s) | 2 positions per orbital (±½) |
| Pauli Exclusion principle | No two electrons in an atom can have the same set of four quantum numbers |
| Aufbau principle | the arrangement of electrons is determined by adding electrons to an atom with a lower atomic number |
| Hund's rule | As electrons fill a sublevel, all orbitals receive one electron with the same spin before electrons pair up |
| isotopes | atoms with the same number of protons but different numbers of neutrons |
| mass number (A) | sum of protons and neutrons |
| valence electrons | electrons in the outermost energy level (highest principle quantum number) |
| anions | negative charge |
| cations | positive charge |
| Raymond Damadian | pioneered magnetic resonance imaging (MRI) |
