I think it's more likely that they're two different approaches. The first one sounds more approachable, and I think there will be more patience with people who don't have a natural passion for chemistry specifically. The second one sounds like it will be populated with people who already took a bunch of AP Chem classes in high school. If you like Chemistry and WANT a really intense class, then go ahead and take the second one.

As for taking them in succession - well, if you take the first one and like it and think it's easy, then you'll know if you WANT to take the second one, and by then you'll have some familiarity with the elements and formulas, so it should definitely be easier to digest. The question is whether you'll be gaining something by doing this, ie: will it be like taking the advanced version of the same class rather than advancing to the next thing.

Can you ask the professors about this? They'll probably have a good idea of the benefits of each class and whether it makes sense to take one as a precursor to the other.