In the reaction mechanism, what does the curly arrow represent?

In organic chemistry, the curly arrow is a symbolic representation used to illustrate the movement of electrons during a chemical reaction. Specifically, the tail of the arrow indicates the starting point of the electron movement, typically from a nucleophile or a bonding pair of electrons, while the head of the arrow indicates where the electrons are moving to, which may be towards an electrophile or a location where a bond will form.

Understanding the role of curly arrows is critical for analyzing reaction mechanisms as they delineate how bonds break and form, allowing one to predict the products of a reaction. The movement of electrons is fundamental to understanding nucleophilic attacks, electrophilic additions, and many other processes in organic chemistry.

Other choices, while related to the context of chemical reactions, do not accurately reflect the specific function of the curly arrow. For instance, the movement of a proton refers to acid-base chemistry and is not represented by a curly arrow in the same way that electron movement is. Broken bonds and the formation of products are outcomes of reactions that may be inferred from the electron movement, but they do not directly explain what the curly arrow signifies.