Final answer:
To determine the configuration of a chiral center, the Cahn-Ingold-Prelog priority rules are used, wherein the atomic number dictates priority, and the spatial arrangement determines if the configuration is R (clockwise) or S (counterclockwise). Fisher projections aid in this determination by visually representing spatial arrangements. R and S descriptors reflect a molecule's absolute configuration for each chiral center.
Step-by-step explanation:
To determine the configuration of a given chiral center, we implement the Cahn-Ingold-Prelog priority rules. The first step in this process is to assign a priority based on the atomic number of the atoms attached to the chiral center. The highest atomic number gets the highest priority. In instances where a tie occurs, such as between two carbon groups, we look further along the attached chain to break the tie.
The next step involves arranging the molecule so that the lowest priority group (often a hydrogen atom) is projected away from us. Then, we observe the sequence from the highest to the lowest priority group. If the sequence is clockwise, the configuration is R (rectus). If it is counterclockwise, the configuration is S (sinister).
Fisher projections can also be useful in determining chiral centers. These two-dimensional representations use horizontal lines for bonds projecting towards the viewer and vertical lines for bonds projecting away. The configuration can then be determined by applying the same priority rules.
It is important to note that stereochemical descriptors R or S are part of the nomenclature and reflect the absolute configuration of chiral centers. For molecules with more than one chiral center, each will have its own R or S designation.