| A | B |
|---|
| atoms | the fundamental building blocks that make up all matter |
| nucleus | cenral part of the atom that contains protons and neutrons |
| subatomic particles | smaller particles that form the atom; protons, neutrons, and electrons |
| proton | subatomic particle with mass of 1 amu and 1 unit of positive charge |
| neutron | subatomic particle with mass of 1 amu and no charge |
| electron | subatomic particle with virtually no mass and 1 unit of negative charge |
| continuous theory of matter | concept that a solid body can be indefinately divided into smaller and smaller pieces |
| discontinuous theory of matter | matter is composed of small indestructible particles called atoms |
| Democritus | ancien Greek philosopher who first proposed the existence of atoms |
| law of conservation of mass | matter can neither be created or destroyed |
| Antoine Lavoisier | his combustion experiments provided evidence for the law of conservation of mass |
| law of definite proportions | the proportion by mass of the elements in a given compound is always the same |
| Joseph Proust | provided experimental evidence to support the law of definite proportions |
| law of multiple proportions | the masses of one element that combined with a fixed mass of another element always form simple whole number ratios |
| John Dalton | proposed first scientific theory for the existence of atoms |
| Dalton's Atomic Theory | elements made of atoms; atoms of ame elements are the same; atoms of different elements are different; compunds form by joining atoms; atoms indivisible |
| Modern Atomic Theory | atoms composed of subatomic particles; can be changed but not by chemical reactions; isotopes are atoms of same element with different masses |
| William Crookes | invented Crookes vacuum tube to study gases, forerunner of CRT, described "cathode rays" |
| JJ Thompson | proposed cathode rays composed of negative particles called electrons in 1897 |
| Ernest Rutherford | provided experimental evidence for the existence of positive particles, protns, in the atom |
| Robert Millikan | his oil drop experiment measured the charge of the electron |
| Rutherford Nuclear Model of Atom | gold foil experiment determined that most of atom was composed mostly of empty space |
| Bohr Energy Level Model of Atom | modified Rutherford model to say that electrons stayed in fixed orbits called energy levels |
| ground state | electron in lowest stable energy levels |
| excited state | electrons absorb energy and are raised to higher less stable energy levels |
| quantum | amount of energy needed to move an electron from one energy level to the next highest energy level |
| K level | lowest energy level in Bohr model; holds 2 electrons |
| L level | second energy level in Bohr model; holds 8 elecrons |
| M level | third energy level in Bohr model; holds 18 electrons |
| Charge Cloud model of Atom | electrons form a diffuse cloud around nucleus |
| orbital | most likely place to find elecrons with specific energy values; form sublevels of Bohr' energy levels |
| Max Planck | proposed quantum theory to explain the nature of light, in which light is made of decrete bundles of energy |
| quantum | descrete amount of energy found in a particle of light |
| photon | fundamental unit of light; discrete package of light energy |
| wavelength | distance between two peaks or troughs of a wave; represented by Greek letter lambda |
| frequency | the number of wave peaks that pass a fixed point each second; ccycles per second = 1 peak per second |
| hertz | SI unit of frequency; 1 hertz = 1 cycle per second |
| wave velocity | is the distance a peak moves in a unit of time; velocity = frequency x wavelength |
| electromagnetic radiation | all forms of wave energy which moves at the speed of light through a vacuum |
| speed of light (c) | 3.0 times 10 to the power of 8 meterrs per second |
| continuous (visible) spectrum | the band of continuous colored light formed when beam of white light passes through a prism |
| bright line spectra | light released by heating chemicals when passed through a prism produce separated lines of colored light; unique to specific elements |
| Planck's constant | constant that expresses proprtionality of light energy to the frequency of the radiation; 6.6 times 10 to -34 power joule/hertz |
| Light Energy equation | Energy = Planck' constant times frequency |
| nucleons | atomic particles found in the atoms nucleus; protons and neutrons |
| atomic number | number of protons in the nucleus of an element; used to identify elements; Z |
| James Chadwick | discovered neutral particle in atom with mass similar to proton in 1932 |
| isotope | atoms of same element with different masses due to differences in numbers of neutrons |
| protium | hydrogen isotope with mass of 1; has only 1 proton |
| deuterium | hydrogen isotope with mass of 2; has 1 proton and 1 neutron |
| tritium | hydrogen isotope with mass of 3; 1 proton and 2 neutrons |
| quarks | smaller particles that make up protons and neutrons discovered through use of particle accelerators |
| up quark | part of proton and neutron with 2/3 + charge |
| down quark | part of proton and nuetrons with 1/3 - charge |
| quarks in a proton | 2 ups + 1 down |
| quarks in a neutron | 2 downs + 1 up |
| Mass Number | total mass of a given atom determined by the sum of its protons and neutrons |
| Atomic Mass | "average" mass of the mixture of elemental isotopes found in a natural sample of an element |
