This document summarizes key concepts related to NMR spectroscopy, including shielding effect, hydrogen bonding, and chemical exchange. It describes how the shielding effect causes some nuclei to experience less of an external magnetic field, requiring a higher frequency for resonance. Hydrogen bonding causes deshielding and higher chemical shift values as electron density around protons decreases. Chemical exchange refers to nuclei switching environments, which can lead to sharp, broad, or coupled peaks depending on the exchange rate relative to peak separation.