nonmetal vs nonmetallic

nonmetal is a noun but nonmetallic is not a noun.

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

As adjectives, nonmetal and nonmetallic are synonyms defined as:

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

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

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