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Overall Chemistry summary:

An important type of reaction in organic chemistry is a nucleophilic substitution reaction. A nucleophilic substitution reaction occurs when a nucleophile (either a single atom or several atoms bonded together) is attracted to a positive charge or a nucleus. A nucleophile is usually a negatively charged group, and in a nucleophilic substitution reaction, it is replaced by another. A nucleophile can be a single atom such as a halide (such as chlorine or iodine), denoted by X, or a molecule with a negative charge (alcohol functional groups (OH) or a cyanide group (CN)). Some nucleophiles are more negatively charged, and therefore, better nucleophiles than others.

There are two types of nucleophilic substitution reactions: unimolecular and bimolecular, refered to as Sn1 and Sn2, respectively. In this case, we are talking about an Sn1 reaction, which takes place in several steps. The word Sn1 comes from the fact that the rate determining step for an Sn1 reaction consists of only one substance; an Sn1 reaction consists of only one nucleophile interacting with the central carbon atom at all times.

Part 1 Concept: Just Leave (Carbocation formation) Condensed Summary / Extended summary
Part 2 Concept: Safety Net (Hyperconjugation) Condensed Summary / Extended summary
Part 3 Concept: Behind Your Back (SN2 reaction) Condensed Summary / Extended summary
Part 4 Concept: Rearrangement (Rearrangement)Condensed Summary / Extended summary
Part 5 Concept: When All Else Fails (Nucleophilic attack) Condensed Summary / Extended summary