subatomic particles - determine the atom's characteristics
- electronic charge - 1.602*10-19 coulombs
- atoms have the same number of protons/electrons, no net charge
- atomic mass unit (amu) - used to measure atomic mass; equal to 1.66054 x 10-24 grams, 1/12 the mass of a carbon-12 atom
- angstrom - 10-10 meters; along w/ picometers, used to express atomic diameters;
- atomic diameter equal to about 1-5 angstroms, atomic nuclei equal to about 10^-4 angstroms
- interiors of collapsed stars may approach the density within atomic nuclei
basic forces - 4 basic interactions in nature
- gravity - attraction between all objects in proportion to their masses; incredibly small between atoms
- electromagnetism - forces between electrically charged objects
- strong nuclear force - acts between subatomic particles in the nucleus to keep them together
- weak nuclear force - weaker than electrical forces, but stronger than gravity; shows up in certain types of radioactivity
isotope - elements that differ in number of neutrons
- atomic number - number of protons
- atomic mass - number of protons/neutrons
- nuclide - atom of a specific isotope
- average atomic mass - found by using the masses of all its isotopes and their relative abundance; aka atomic weight
periodic table - developed in 1869
- similar elements placed in the same column (group)
- chemical/physical properties show repetition
- metallic elements - on the left/middle part of the periodic table; shiny, malleable, conductors
- nonmetallic elements - separated from metals on the table by a diagonal line from boron to astatine; brittle, dissolves to form salt, insulators
- metalloids - elements that have properties falling between metals/nonmentals; shiny/brittle
- 8A - unreactive, inert/noble gases; no charge
- 1A - alkali metals; +1 charge
- 2A - alkaline earth metals; +2 charge
- 6A - chalcogens; -2 charge
- 7A - halogens; -1 charge
Subject:
Subject X2:
