| Term | Definition |
|---|
| period | rows of the periodic table |
| groups | columns of the periodic table |
| group 1a | alkali metals |
| group 2a | alkaline earth metals |
| group 6a | chalcogens |
| group 7a | halogens |
| group 8a | inert gases |
| atom | the basic structural unit of an element; the smallest unit of an element that retains the chemical properties of that element |
| the three primary particles of an atom | electrons, protons, neutrons |
| nucleus | the small, dense, positively charged region in the center of the atom |
| what do you find in the nucleus? | protons and neutrons |
| protons and electrons are _______ but ______ | equal in charge, opposite in sign |
| a neutral atom | has the same number of protons and electrons |
| where is the charge of the particle written? | upper right |
| where is the mass number written? | upper left |
| where is the atomic number written? | lower left |
| atomic number | the number of protons in the atom; gives the atom its identity |
| mass number | the sum of the number of protons and neutrons |
| mass of a proton | 1 |
| isotopes | atoms of the same element having different masses; same protons, different neutrons |
| how to determine atomic mass | (% abundance)(mass isotope 1) + (%abundance)(mass of isotope 2) + etc. |
| ion | electrically charged particles that result from a gain or loss of one or more electrons by the parent atom |
| cation | positively charged ion |
| anion | negatively charged ion |
| dalton's atomic theory | the first experimentally based theory of atomic structure of the atom |
| postulate's of dalton's atomic theory that sill hold true today | all matter consists of tiny particles called atoms, atoms of different elements combine in simple whole-number ratios to produce compounds (stable aggregates of atoms), and chemical change involves joining, separating or rearranging atoms |
| what did the gold foil experiment discover? | most of the atom is empty space and the majority of the mass is located in a small, dense region |
| spectroscopy | the absorption or emission of light by atoms |
| what is spectroscopy used for? | to understand the electronic structure |
| wavelength | the distance between identical points on successive waves |
| what two aspects of electromagnetic radiation determine energy? | wavelength and frequency |
| a shorter wavelength corresponds to | higher energy |
| bohr's theory | atoms can absorb and emit energy via promotion of electrons to higher energy levels and relaxation to lower levels |
| quantization of energy | electrons exist in fixed energy levels surrounding the nucleus |
| excited state | promotion of electron occurs as it absorbs energy |
| relaxation | energy is released as the electron travels back to lower levels |
| orbit | the fixed energy level |
| ground state | the lowest possible energy state |
| modern atomic theory | electrons do not move in orbits |
| atomic orbitals | regions in space with a high probability of finding an electron |
| principal quantum numbers | the number of "packets" around an atom where electrons can exist |
| the larger the value of n, | the higher the energy level and farther away from the nucleus the electrons are |
| the number of sublevels in a principal energy level equals | n |
| sublevels | s, p, d, f |
| n = 1, l = | 1s |
| n=2, l = | 2s, 2p |
| n=3, l= | 3s, 3p, 3d |
| n=4, l= | 4s, 4p, 4d, 4f |
| orbital | a specific region of a sublevel containing a maximum of two electrons |
| the shape of the s orbital | sphere |
| the shape of the p orbital | dumbbell |
| magnetic quantum number | the number of orbitals in a sublevel |
| m = | -L, ... 0, ... L |
| number of orbitals in the s subshell | 1 |
| number of orbitals in the p subshell | 3 |
| number of orbitals in the d subshell | 5 |
| number of orbitals in the f subshell | 7 |
| electron configuration | the arrangement of electrons in atomic orbitals |
| aufbau principle relates to | electron configuration |
| electrons fill the ____ orbital first | lowest available energy |
| an atom is energetically stable when | it has a full outer shell |
| order of energy levels up until 5p | 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p |
| short hand for electron configuration | [previous noble gas]outer shell configuration left over |
| metals | elements that tend to lose electrons during chemical change, forming positive ions |
| nonmetals | elements who atoms tend to gain electrons during chemical change, forming negative ions |
| metalloids | elements that have intermediate properties between metals and nonmetals |
| valence electrons | outermost electrons; only ones involved in chemical bonding |
| octet rule | elements usually react in such a way as to attain the electron configuration of the noble gas closest to them in the periodic table |
| atomic size trend | the size of an element increases moving down a group and decreases moving from left to right across a period |
| why are elements on the right of the table smaller than those on the left? | the electrons are pulled closer to the nucleus |
| why are the elements at the bottom of the table bigger than those at the top? | they have more shells, and each successive shell is located further from the nucleus |
| cations are ____ than their parent atom, and why? | smaller, more protons than electrons makes it easier to pull remaining electrons closer to the nucleus |
| anions are _____ than their parent atom, and why? | bigger, more electrons than protons makes it more difficult to pull the remaining electrons towards the nucleus |
| ionization energy | the energy required to remove an electron from an isolated atom |
| the lower the ionization energy, | the easier it is to form a cation |
| electron affinity | the energy released when a single electron is added to an isolated atom |
| large electron affinity indicates that an atom: | becomes more stable as it forms an anion |
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