Yes, METALS is a Scrabble word!

Letter values in Scrabble US: M 3, E 1, T 1, A 1, L 1, S 1.

Is it a valid word?

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

any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.
a mixture containing two or more metallic elements or metallic and nonmetallic elements usually fused together or dissolving into each other when molten

Also: metallic element.