click below
click below
Normal Size Small Size show me how
vocab chps 12 & 13
Stack #59956
| word | definition |
|---|---|
| element | a pure substance that cannot be seperated or broken down into simpler substances by physical or chemical means |
| compound | a pure substance composed of two or more elements that are chemically combined |
| mixture | a combination of two or more substances that are not chemically combined |
| atom | the smallest particle into which an element can be divided and still retain all of the properties of that element |
| proton | the positivley charged particles of the nucleus |
| electron | the negativley charged particles found in all atoms |
| neutron | the particles of the neucleus that have no charge |
| periodic | having a regular, repeating pattern |
| periodic law | a law that states that the chemical and physical properties of elements are periodic functions of their atomic numbers |
| atomic number | the number of protons in the neucleus of an atom |
| atomic mass | the weighted average of the masses of particles in atoms |
| isotope | atoms that have the same number of protons but have different number of neutrons |
| valence electron | the electrons in the outermost energy level of an atom |
| John Dalton | atomic theory |
| Ernest Rutherford | positve charge nucleus, atom mostly empty space electrons travel around the nucleus |
| Niels Bohr | electrons travel in clouds |
| Democritus | 1st to come up with the idea of an atom |
| Dmitri Mendeleev | father of the periodic table, aranged elements by atomic mass |
| Henry Moseley | rearranged periodic table by atomic number |
| J. J. Thomas | small particles in atom |