atom vs atomic

atom is a noun but atomic is not a noun.

Word	Noun	Adjective	Verb	Adverb
atom	Yes	No	No	No
atomic	No	Yes	No	No

atom (noun)	atomic (noun)
(physics and chemistry) the smallest component of an element having the chemical properties of the element
(nontechnical usage) a tiny piece of anything

atom (adjective)	atomic (adjective)
	(weapons) deriving destructive energy from the release of atomic energy
	of or relating to or comprising atoms
	immeasurably small