Help about college?

I'm will be a high school junior in the fall. I have always gotten straight a's, except I got a B+ in chem this year (horrible teacher, and I would take responsibility, but it is NOT my fault). But my GPA is still a 4.0 because I took an AP this year. Next year I am taking 4 AP's and 5 as a senior, so as long as I get a's in those I will still have a GPA well over 4.0. I am in one of the most rigorous schools in the US. I get perfect/almost perfect on my standardized tests (SAT's, SAT II's, PSAT, etc.)I also do three sports and participate in many clubs, which I have taken leadership positions in, as well as charity work. BUT: I am really worried that this B+ will blow my chances of getting into an Ivy League college (like Yale, Princeton, Harvard) because they can just see it as a reason to cut me. Will it make a difference if I take AP chem as a senior, and get an A in that, so they can see that I do know chem, and not a complete idiot. Any answers? 10 points to the best one