| Question |
Answer |
| law of conservation of mass | the law that states that mass cannot be created or destroyed in ordinary chemical and physical changes. |
| law of definite proportions | the law that states that a chemical compound always contains the same elements in exactly the same proportions by weight or mass. |
| law of multiple proportions | the law that states that when an element combines to form two or more compounds, the mass of the element that combines with a given mass of the other is in the ratio of small whole numbers. |
| atom | the smallest unit of an element that maintains the chemical properties of that element. |
| nuclear forces | the interaction that binds protons and neutrons, protons and protons, and neutrons and neutrons together in a nucleus. |
| atomic number | the number of protons in the nucleus of an atom. |
| average atomic mass | the weighted average of the mass of all naturally occurring isotopes of an element. |
| mass number | the sum of the numbers of protons and neutrons in the nucleus of an atom. |
| electromagnetic spectrum | all of the frequencies or wavelenghts of electromagnetic radiation. |
| excited state | a state in which an atom has more energy than it does at its ground state. |
| frequency | the number of cycles or vibrations per unit of time; also the number of waves produced in a given second of time. |
| ground state | the lowest energy state of a quantizied system. |
| wavelength | the distance from any point on a wave to an identical point on the next wave. |
| angular momentum quantum number | the quantum number that indicates the shape of an orbital |
| Heisenberg Uncertainty Principle | the principle that states that determining both the position and velocity of an electron or any other particle simultaneously is impossible. |
| magnetic quantum number | the quantum number that corresponds to the alingment of the angular momentum component with a magnetic field. |
| orbital | a region in an atom where there is high probability of finding electrons. |
| principal quantum number | the quantum number that indicates the energy and orbital of an electron in an atom. |
| quantum numbers | a number that specifies the properties of electrons. |
| quantum theory | the study of the structure and behavior of the atom and of subatomic particles from the view that all energy comes in tiny indivisible bundles. |
| spin quantum numbers | the quantum number that describes the intrinsic angular movement of a particle. |
| Aufbau principle | the principle that states that the structure of each successive element is obtained by adding one proton to the nucleus of the atom and one electron to the lowest-energy orbital that is available. |
| electron configuration | the arrangement of electrons in an atom. |
| Hund's rule | the rule that states that for an atom in the ground state, the number of unpaired electorns is the maximum possible and those unpaired electrons have the same spin. |
| noble gases | one of the elements of group 18 of the periodic table; are unreactive. |
| Pauli exclusion principle | the principle that states that two particles of a certain class cannot be in exactly the same energy state. |
| highest occupied level | the electron-containing main energy level with the highest principal quantum number. |
| inner-shell electrons | electrons that are not in the highest-occupied energy level. |
| noble-gas configuration | an outer main energy level fully occupied, in most cases, by eight electrons. |
Ch.18 LTI-MA 509
