| A | B |
|---|
| triad | group of three elemenst that have similar properties, developed by Dobriener |
| law of octaves | idea that similiar properties repeated every eight elements; developed by Newlands |
| period | a row on the perioidic table |
| atomic mass | the mass of an element, it is measured in atomic mass units (AMU) [This numer has decimals] |
| atomic number | the number of protons in an element, first determined by Mosely. Used to arrange the perioidic table. |
| periodic law | the elements in the periodic table are arranged in order of increasing atomic number. (When Mendeleev first developed this, he used atomic mass. IT was changed with the determinatin of atomic number.) |
| periodicity | a regular repeating pattern; spcifically in the chemical and physical properties on the periodic table |
| family | a column on the perioidic table |
| group | a column on the periodic table |
| representative elements | those elements identified by the number of electrons in their s and p sublevels; groups 1,2,13-18 |
| alkali metals | metals in the first column of the periodic table, configurationends in s1 |
| alkaline earth metals | elements in the second column of the periodic table; configurationends in s2 |
| chalcogen | also known as the oxygen family; group 16 on the periodic table; configuration ends in p4 |
| halogen | group 17 on the periodic table, configurations end in p5 |
| noble gases | group 18 on the periodic table; configuations end in p6, are stable |
| transition metal | elements in groups 3-12; identified by the number of electrons in the d sublevel |
| inner transition metal | Also known as the rare earth elements |
| lanthanide series | Numbers 58-71, Bottom row pulled out of the periodic table, part of f sublevel |
| actinide series | Numbers 90-103, bottom row pulled out of the periodict table. part of f sublevel |
| metal | metallic, malleable, ductile, good conductor. Forms cations when ionizing |
| nonmetal | elements found on the right hand side of the peroidic table. They are gas or brittle solids at room temperature.. They are poor conductors |
| metalloid | series of elements that tend to have properties both like metals and nonmetals |
| octet rule | an atom with eight electrons in its outer energy level is very stable |
| cation | positively charged atom |
| anion | negatively charged atom |
| isoelectronic | when the electron configuration of an ion matches the noble gas configuration closest to it. |
| atomic radii | the measurement of atomic size by measuring the radius of the atom |
| shielding effect | when the inner energy level electrons sheild the outer ones from the increased pull of the nucleus |
| ionization energy | the energy required to remove one electron from the gaseous form of an element |
| electronegativity | the attraction an atom has for a shared pair of electrons |
| reactivity | the description of how an atom reacts |
| ionic charge | the charge an atom has when it gains or loses electrons |
| valence electrons | those elements in the outer energy level of an atom, specifically in the s and p sublevels |
