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Chem 105 Ch 2
| Term | Definition |
|---|---|
| Subatomic particles | protons, neutrons, and electrons |
| Thomson cathode ray tube experiment | found mass-to-charge ratio of election |
| Cathode rays | beam of electrons |
| Electrons | negatively charged subatomic particle with a very small mass (9.109x10^-31g) |
| Millikan oil drop experiment | mass of an electron |
| Cations and anions | positive and negative ions respectively |
| Rutherford gold foil experiment | shot positive helium nuclei at gold foil, most go through, some reflected a little, some completely; found most of atom is empty space with a dense nucleus |
| Atomic nucleus | nucleus contains protons and neutrons, protons always the same for an element, neutrons may differ |
| Atomic mass units | one twelfth the mass of carbon 12 |
| 1 amu | 1.66054x10^-27 kg |
| Nuclide/isotope | different number of neutrons |
| Atomic number | number of protons |
| Mass number | sum of protons plus neutrons |
| Periodic table | chart of elements in order of atomic number, reflect physical |
| Periods | rows |
| Groups | columns |
| Main group elements | everything but |
| Metals | everything left of metalloids |
| Alkali metals | group 1 |
| Alkaline earth metals | group2 |
| Transition metals | d level |
| Metalloids | steps |
| Nonmetals | not a metal, right of metalloids |
| Halogens | group 17 |
| Noble gases | group 18 |
| Atomic mass | weighted average of natural abundance of isotopes |
| Natural abundances | percentage of |
| Formula mass | for formula unit |
| Mole | chemist's dozen |
| Avogadro’s number | 6.0221x10^-23 |
| Molar mass | mass per mole of an element |