Yes, IDEALIZATION is a Scrabble word!

Letter values in Scrabble US: I 1, D 2, E 1, A 1, L 1, I 1, Z 10, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

a portrayal of something as ideal
(psychiatry) a defense mechanism that splits something you are ambivalent about into two representations--one good and one bad
something that exists only as an idea

Not playable in Scrabble US: IDEALISATION.