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Chapter 5 Vocabulary
Term | Definition |
---|---|
Periodic table | An arrangement of elements in columns, based on a set of properties that repeat from row to row. |
Period | A row in a periodic table of elements; the time required for one complete cycle of a periodic motion; a unit of geologic time into which geologists divide eras. |
Group | A column of elements in a periodic table. |
Periodic law | The pattern of repeating properties displayed by elements in the periodic table. |
Atomic mass unit (amu) | One twelfth the mass of a carbon-12 atom. |
Metals | Elements that are good conductors of heat and electric current. |
Transition metals | Elements that form a bridge between elements on the left and right sides of the periodic table. |
Nonmetals | Elements that are poor conductors of heat and electric current. |
Metalloids | Elements with properties that fall between those of metals and nonmetals. |
Valence electron | An electron that is in the highest occupied energy level of an atom. |
Alkali metals | The elements in group 1A of the periodic table, not including hydrogen. |
Alkaline earth metals | The elements in group 2A of the periodic table. |
Halogens | The elements in group 7A of the periodic table. |
Noble gases | The elements in group 8A of the periodic table. |