The atomic weights of O2, CO, CO2 and N2 are fairly similar, and the overriding influence of convection and localised air pressures (and a myriad of other reasons) keeps them mixed. If 'air' behaved as a still liquid, then we'd have distinct layers of each gas, which wouldn't be very healthy for humans.
Stop trying to derail the thread with posts that are clearly beyond your level of comprehension Blueflame.