chemical science vs valence

chemical science and valence both are nouns.

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

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