| A | B |
|---|
| protons | positively charged subatomic particle |
| electrons | negatively charged subatomic particle |
| neutrons | subatomic particle with no charge |
| nucleus | center, dense, positively charged part of atom |
| Dalton | said all things were made of atoms |
| Thomson | discovered the electron; plum pudding model |
| Rutherford | discovered the nucleus of the atom |
| Bohr | said electrons orbit the nucleus in energy levels |
| neutral | same number of protons and electrons |
| ions | atoms that have a charge |
| isotope | atoms of the same element but different masses |
| atomic number | number of protons in an atom |
| atomic mass | protons plus neutrons |
| valence electron | outermost electrons in an atom |
| oxidation number | charge of an atom |
| alkali metals | extremely reactive group of metals with 1 valence electron |
| alkali earth metals | reactive metals with 2 valence electrons |
| halogens | reactive gases with 7 valence electrons |
| noble gases | unreactive group pof gases |
| metals | shiny, malleable section of elements on the left side of the periodic table |
| nonmetals | mostly gases on the right side of the periodic table |
| groups | "families"; columns on the periodic table |
| periods | rows on the periodic table |
| fission | division of nucleus |
| fusion | bringing together of 2 smaller nuclei |
