In the R- and S- system, how are chemical groups classified?

In the R- and S- nomenclature system, chemical groups are classified based on their priority in relation to the Cahn-Ingold-Prelog rules. This system assigns priorities to substituents attached to a chiral carbon atom based on atomic number, where higher atomic numbers take precedence. If two groups have the same atom, the priority is determined by the next set of atoms in the chain. This prioritization helps in identifying the configuration of the chiral center as either R (rectus, Latin for right) or S (sinister, Latin for left) depending on the orientation of the highest priority groups when viewed from a specific perspective. Thus, the classification based on priority is essential for the accurate determination of molecular stereochemistry in chiral molecules.