chemical science vs valent

chemical science is a noun but valent is not a noun.

Word	Noun	Adjective	Verb	Adverb
chemical science	Yes	No	No	No
valent	No	Yes	No	No

chemical science (noun)	valent (noun)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions

chemical science (adjective)	valent (adjective)
	(chemistry) having valence; usually used in combination