Yes, CHLORINE is a Scrabble word!

Letter values in Scrabble US: C 3, H 4, L 1, O 1, R 1, I 1, N 1, E 1.

Is it a valid word?

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

a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water)

Also: atomic number 17.

Not playable in Scrabble US: CL.