| 释义 |
va·lence
\ˈvālən(t)s\ noun
(-s)
Etymology: Late Latin valentia power, capacity, from Latin valent-, valens (present participle of valēre to be strong) + -ia -y — more at wield
1.
a. : the degree of combining power of an element or radical : the number of atoms of hydrogen, sodium, fluorine, or other univalent element with which an atom of the element or a molecule of the radical will combine by means of bonds or for which it can be substituted or with which it can be compared : the oxidation state of an element in a compound
< potassium has a valence of one because a gram atom combines with a gram atom of hydrogen to form potassium hydride KH or with a gram atom of fluorine to form potassium fluoride KF >
< iron has a variable valence; two in ferrous chloride FeCl2 and three in ferric chloride FeCl3 >
— see covalence, electrovalence; compare coordinate bond, polar valence 2
b. : a unit of valence
< the four valences of carbon >
2.
a. : relative capacity to unite, react, or interact (as with antigens or a biological substrate)
b. : the degree of attractiveness an individual, activity, or object possesses as a behavioral goal
< the group may have a positive valence for member A because he has friends in it — Neal Gross & W.E.Martin > |