In the R,S system, which of the following alkyl groups has lowest priority?
A) butyl
B) ethyl
C) methyl
D) propyl

Question

Quizplus · Accepted Answer

In the R,S system, priority is determined based on the atomic number of the atoms directly attached to the stereocenter. Since carbon has a higher atomic number than hydrogen, alkyl groups are ranked based on the number of carbons they have. Thus, the methyl group (one carbon) has the lowest priority, while the butyl group (four carbons) has the highest priority. Therefore, choice C (methyl) has the lowest priority.

In the R,S System, Which of the Following Alkyl Groups