In beginning to tackle this problem, we are given three crucial pieces of information in the question:
- all flasks are to be filled separately to a volume of 1 litre,
- all flasks are at the same temperature, and
- all flasks are at the same pressure.
When we refer this information back to the ideal gas equation, which is itself derived from the Boyle's, Charles's, and Avogadro's Laws, we realise that the number of moles of gas will therefore be constant in each case.
Again, since the values of
We're looking at atoms, though, and that's where things are a bit different! Although we have appreciated that the number of instances of the species present in the flask is the same in all cases- though we do not know that value - we have not yet considered how many atoms constitute each individual species.
So all your ratio really boils down to is the number of atoms that constitutes each species, since filling to a constant volume under shared temperature and pressure conditions will always result in the same number of moles of gas present in a container.