资料来源 : pyDict

原子价

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Valence \Va"lence\, n. [From L. valens, -entis, p. pr. of valere
   to have power, to be strong. See {Valiant}.] (Chem.)
   The degree of combining power of an atom (or radical) as
   shown by the number of atoms of hydrogen (or of other monads,
   as chlorine, sodium, etc.) with which it will combine, or for
   which it can be substituted, or with which it can be
   compared; thus, an atom of hydrogen is a monad, and has a
   valence of one; the atoms of oxygen, nitrogen, and carbon are
   respectively dyads, triads, and tetrads, and have a valence
   respectively of two, three, and four.

   Note: The valence of certain elements varies in different
         compounds. Valence in degree may extend as high as
         seven or eight, as in the cases of iodine and osmium
         respectively. The doctrine of valence has been of
         fundamental importance in distinguishing the
         equivalence from the atomic weight, and is an essential
         factor in explaining the chemical structures of
         compounds.

资料来源 : WordNet®

valence
     n 1: (biology) a relative capacity to unite or react or interact
          as with antigens or a biological substrate [syn: {valency}]
     2: (chemistry) a property of atoms or radicals; their combining
        power given in terms of the number of hydrogen atoms (or
        the equivalent) [syn: {valency}]