Yes, HELIUM is a Scrabble word!

Letter values in Scrabble US: H 4, E 1, L 1, I 1, U 1, M 3.

Is it a valid word?

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

a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas)

Also: atomic number 2.