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Periodic Law

when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties


good conductors of heat and electric current; metals tend to be shiny, ductile, and malleable


poor conductors of heat and electric current


have properties that are similar to those of metals and nonmetals

alkali metals

any metal in gropu 1A of the periodic table

alkaline earth metals

any metal in group 2A of the periodic table

noble gases

an element in group 8A of the periodic table; the s and p sublevels of the highest occupied energy level are filled

representative elements

an element in an A group in the periodic table; as a group these elements display a wide range of physical and chemical properties. In their atoms, the s an p sublevels in the highest occupied energy level are partially filled

transition metals

one of the group B elements in which the highest occupied s sublevel and a nearby d sublevel generally contain electrons

inner transition metals

an element in the lanthanide or actinide series; the highest occupied s subevel and a nearby f sublevel of its atoms generally contain electrons; also called inner transition element


a horizontal row of elements in the periodic table


a vertical column of elements in the periodic table

Periodic table

an arrangement of elemetns in which the elements are separated into groups based on a set of repeating properties


non-metals of group 7A


an atom of group of atoms that has a positve or negative charge


any atom of group of atoms with a negative charge

atomic radius

one-half the distance between the nuclei of two atoms of the same element when the atoms are joined


the ability of an atom to attract electrons when the atom is in a compound


any atom or group of atoms with a positive charge

ionization energy

the energy requried to remove an electron from an atom in its gaseous state

ionic radius

decreases for cations and anions from left to right across a period

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