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FPC - The Periodic Table - Ch 5
an arrangement of elements in columns, ordered according to atomic numbers
the horizontal rows of the periodic table of the elements
the vertical columns of the periodic table of the elements
the repetition of a set of properties, row after row
atomic mass unit (amu)
units used to measure the mass of atoms; defin ed as 1/12 the mass of carbon-12
elements that are good conductors of heat and electricity
elements that form a bridge between the elements on the left and right sides of the periodic table
elements that are poor conductors of heat and electricity
elements with properties that fall between those of metals & nonmetals
the electron(s) that are in the outermost energy level of an atom
elements of group 1A; have 1 valence electron and are highly reactive
alkaline earth metals
elements of group 2A; have 2 valence electrons and are reactive
elements of group 7A; have 7 valence electrons and are highly reactive
elements of group 8A; have 8 valence electrons (exception is He) and are inert
Variation across a period
From left to right, the elements become less metallic and more nonmetallic in their properties.