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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 |