Yes, FATALISM is a Scrabble word!

Letter values in Scrabble US: F 4, A 1, T 1, A 1, L 1, I 1, S 1, M 3.

Is it a valid word?

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

a submissive mental attitude resulting from acceptance of the doctrine that everything that happens is predetermined and inevitable
a philosophical doctrine holding that all events are predetermined in advance for all time and human beings are powerless to change them