Will a discontinued class look bad on my resume?

So in my school there is pretty strict graduation requirement that everyone needs 4 years of English, 3 years of math, 3 years of history, etc. I really want to take AP Chemistry in junior year but that automatically forces me to take a physics class as well. I’ve been doing Orchestra (Advanced Orchestra) in my freshman year and will do it in my sophomore year, but taking these classes means I will need to quit for one year. This also means that I forfeit my opportunities to audition for things like Regional Orchestra, etc. Will colleges look at this badly, seeing that I’ve skipped a year???

Talk to your GC about ramifications. Also consider your options such as taking just chemistry to remain in orchestra and perhaps not ever enroll in physics. The orchestra options seem really enticing.

The typical science sequence is Bio, Chem, Physics and then an AP version.
It is fine just to take Physics and keep orchestra if you like orchestra and then take AP Che or AP Bio next year.
If you feel you must skip orchestra, do not worry about skipping a year because academics is the major thing they look at.