| A | B |
|---|
| Democritus | first to propose the possibility of an atom |
| Dalton | proposed the atomic theory |
| Lavoisier | proposed the law of constant proportions |
| Thomson | experimented with a cathode ray tube |
| electrons | negatively charges particles that orbit the nucleus |
| radioactivity | spontaneous emission of radiation from an element |
| Rutherford | did the gold foil experiment |
| nucleus | center of the atom |
| protons | positively charged particles found in the nucleus |
| neutrons | neutral particles found in the nucleus |
| atomic mass units | units of measurement for mass of parts of an atom |
| atomic number | corresponds to number of protons in an atom |
| ions | atoms possessing a net electrical charge |
| isotopes | atoms that have the same number of protons but a different number of neutrons |
| mass number | number of protons and number of neutrons added together |
| nuclear reactions | changes within the nucleus of an atom |
| strong nuclear force | holds protons and neutrons together |
| alpha particle | consists of a helium nucleus |
| beta particle | consists of an electron |
| gamma particle | consists of high energy non particle radiation |
