chemist vs Dmitri Ivanovich Mendeleyev

chemist and Dmitri Ivanovich Mendeleyev both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemist	Yes	No	No	No
Dmitri Ivanovich Mendeleyev	Yes	No	No	No

chemist (noun)	Dmitri Ivanovich Mendeleyev (noun)
a scientist who specializes in chemistry	Russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements (1834-1907)
a health professional trained in the art of preparing and dispensing drugs