Chirality/Stereochemistry Video Series: Video 2
Chiral carbons are identified as having 4 unique substituents. Finding the Absolute Configuration – R and S comes as a result of ranking and order substituents, specifically by noting the configuration of the top 3 groups.
This video shows you how to prioritize substituents to find R and S configurations using the Cahn-Ingold-Prelog priority rules.
(Watch on YouTube: R/S. Click cc on bottom right for video transcription.)