serial vs sequential

serial is a noun but sequential is not a noun.

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

As adjectives, serial and sequential are synonyms defined as:

Other synonyms of serial include consecutive, sequent, successive.

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

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