bivalent vs valence

bivalent is not a noun while valence is a noun.

Word	Noun	Adjective	Verb	Adverb
bivalent	No	Yes	No	No
valence	Yes	No	No	No

bivalent (noun)	valence (noun)
	(chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)
	(biology) a relative capacity to unite or react or interact as with antigens or a biological substrate

bivalent (adjective)	valence (adjective)
used of homologous chromosomes associated in pairs in synapsis
having a valence of two or having two valences