Yes, LIQUIDS is a Scrabble word!

Letter values in Scrabble US: L 1, I 1, Q 10, U 1, I 1, D 2, S 1.

Is it a valid word?

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

a substance that is liquid at room temperature and pressure
the state in which a substance exhibits a characteristic readiness to flow with little or no tendency to disperse and relatively high incompressibility
fluid matter having no fixed shape but a fixed volume
a frictionless continuant that is not a nasal consonant (especially `l' and `r')

Also: liquid state.