nonmetallic vs nonmetal

nonmetallic is not a noun while nonmetal is a noun.

Word	Noun	Adjective	Verb	Adverb
nonmetallic	No	Yes	No	No
nonmetal	Yes	Yes	No	No

As adjectives, nonmetallic and nonmetal are synonyms defined as:

nonmetallic and nonmetal: not containing or resembling or characteristic of a metal

nonmetallic (noun)	nonmetal (noun)
	a chemical element lacking typical metallic properties

nonmetallic (adjective)	nonmetal (adjective)
not containing or resembling or characteristic of a metal	not containing or resembling or characteristic of a metal