sequential vs serial

sequential is not a noun while serial is a noun.

Word	Noun	Adjective	Verb	Adverb
sequential	No	Yes	No	No
serial	Yes	Yes	No	No

As adjectives, sequential and serial are synonyms defined as:

Other synonyms of sequential include consecutive, sequent, successive.

sequential (noun)	serial (noun)
	a serialized set of programs
	a periodical that appears at scheduled times

sequential (adjective)	serial (adjective)
in regular succession without gaps	pertaining to or occurring in or producing a series
	pertaining to or composed in serial technique
	of or relating to the sequential performance of multiple operations
	in regular succession without gaps