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PT definitions
Definitions for Unit 2: PT
Term | Definition |
---|---|
Periodic Trend | a regular variation of certain characteristics of elements to increase or decrease along a row or column of the periodic table of elements |
Atomic Number | the number of protons in the nucleus of an atom; the number of electron on the electron clouds; used to determine that element's position in the periodic table |
Valence Electrons | electrons in the last shell or energy level of an atom |
Reactivity | tendency of a substance to undergo chemical changes in a system |
Groups | a vertical column that contains elements having the same number of electrons in the outermost shell of their atoms. |
Periods | Any of the seven horizontal rows.All the elements in a particular period have the same number of electron shells in their atoms |