Yes, CONSTITUENTS is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, N 1, S 1, T 1, I 1, T 1, U 1, E 1, N 1, T 1, S 1.

Is it a valid word?

CONSTITUENTS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a system
a member of a constituency; a citizen who is represented in a government by officials for whom he or she votes
something determined in relation to something that includes it
(grammar) a word or phrase or clause forming part of a larger grammatical construction
an abstract part of something

Also: component part, grammatical constituent.