atomic theory vs atomic physics

atomic theory and atomic physics both are nouns.

Word	Noun	Adjective	Verb	Adverb
atomic theory	Yes	No	No	No
atomic physics	Yes	No	No	No

atomic theory (noun)	atomic physics (noun)
(chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles	the branch of physics that studies the internal structure of atomic nuclei
a theory of the structure of the atom