g arrange the gases in order of increasing density when they are all under stp conditions. Argon florine neon chlorine

Florine, Neon, Chlorine and Argon.

Explanation:

The density of a gas varies in direct proportion with its molecular mass. This means, higher molecular mass gases would have higher density and vice versa.

Increasing Density = Increasing Molecular mass

Arranging Argon, Florine, Neon and Chlorine in order of increasing molecular mass, we have;

Florine, Neon, Chlorine and Argon.

it's filtration, but this is an assumption so my apologies if i got this