Advanced Placement was introduced in public high schools in the late 80s as an alternative to the standard high school curriculum. The program replaced many Honors/Gifted programs designed to separate motivated, college bound students. I would like to know the difference between A-Levels vs. AP for STEM subjects. I know that AP Chemistry is intensive because it covers a lot of challenging topics, but what I have found online is that the subjects have so many overlaps. For example, both A-Level and AP Chemistry students study the chemical shifts of molecules like benzene through NMR Spectrum. We all use the same standard compound TMS, trimethylsilane and the formula: Chemical Shift = (Observed Shift from TMS in Hz x 10^6)/(Spectrometer Frequency in Hertz). For example, for benzene, the distance from TMS is 2181 Hz, so 2181/300 = 7.27 if we are dealing with 300 MHz spectrum. We also learn the same topics – the effect of electronegativity on chemical shifts. Methane is more shielded whereas 1-chloromethane is more deshielded due to chlorine. Chlorine is going to withdraw some electron density.