Using the formula PV=nRT (or better use as PV = (g/M) RT where M is the molar mass, if we rearrange the formula to calculate pressure P it gives us
P= gRT/MV.
Using this formula for Oxygen the result is P = 1.53 atm; for Nitrogen , P= 1.75 atm and for Neon, P= 2.44 atm.
Eg calculation for Oxygen P = [2.0 g* 0.0821 L.atm/mol.K *298K] / [32 g/mol * 1 L]
It we really look at the last formula, we should recognize without doing any calculation that as the molar mass M increases for the same mass of different gases, the pressure decreases. This conclusion is for ANY set of gases , not just the three gases given: Larger the molar mass, the smaller the pressure!
Thus the order is Neon > Nitrogen > Oxygen
Hope this explanation helps!
