Yes, DEOXIDIZED is a Scrabble word!

Letter values in Scrabble US: D 2, E 1, O 1, X 8, I 1, D 2, I 1, Z 10, E 1, D 2.

Is it a valid word?

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

to remove oxygen from a compound, or cause to react with hydrogen or form a hydride, or to undergo an increase in the number of electrons

Not playable in Scrabble US: DEOXIDISE.