| A | B |
|---|
| Used a cathode ray tube to discover the electron | J.J. Thomson |
| Discovered the neutron | Chadwick |
| First thought of the existence of the atom | Democritus |
| Developed a tested atomic theory that didn't take into account any subatomic particles | Dalton |
| Developed a model where the location of an electron wasn't exactly defined, its probable location was calculated | Schrodinger |
| Proposed the idea of a nucleus | Rutherford |
| Stated that electrons always move in concentric circles around the nucleus | Bohr |
| Discovered the charge of the electron | Milikan |
