| A | B |
|---|
| Democtrius | first person to say all matter is made of small, unbreakable pieces |
| John Dalton | created atomic theory, a set of rules about atoms that is still used today |
| matter | made from atoms |
| positive | charge of protons |
| negative | charge of electrons |
| neutral | charge of neutrons |
| 1 amu | weight of protons & neutrons |
| .0006 amu | weight of electrons |
| nucleus | location of protons & neutrons |
| electron cloud | location of electrons |
| nucleus | very small, most of the atoms weight |
| electron cloud | very large, almost weightless |
| atomic mass | weight of atom, protons + neturons |
| valence electrons | found in outter energy level |
| electric force | holds atom together |
| electrically neutral | atom that has same number of protons & electrons |
| atomic number | tells number of protons |
| subtract atomic number and atomic mass | way to calculate number of neutrons |
| Bohr dot structure | shows all electrons and energy levels |
| Lewis dot structure | shows the valence electrons |
| ions | an atom that has gained or lost electrons |
| positive charge | an ion that has lost electrons |
| negative charge | an ion that has gained electrons |
| want a full valence | reason atoms become ions |
| cation | ion with a positive charge |
| anion | atom with a negative charge |
| element | determined by the number of protons |
| isotope | atom with a different amount of neutrons |
| average atomic mass | the weight shown on the periodic table |
| Mendeleev | created the periodic table of elements |
| periods | rows across the periodic table |
| # of energy levels | period tells you this about an atom |
| groups | columns on the periodic table |
| # of valence electrons | group number tells you this about an atom |
| family | all the elements in a group on the periodic table |
| similar properties | elements in a family have _____ |
| alkali metals | first family on the periodic table |
| alkaline earth metals | second family on the periodic table |
| halides | second to last family on the periodic table |
| noble gasses | last family on the periodic table |
| a family of elements that does NOT react | noble gasses |
