periodic table vs chemical science

periodic table and chemical science both are nouns.

Word	Noun	Adjective	Verb	Adverb
periodic table	Yes	No	No	No
chemical science	Yes	No	No	No

periodic table (noun)	chemical science (noun)
(chemistry) a tabular arrangement of the chemical elements according to atomic number as based on the periodic law	the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions