SN1 and SN2 rections help

[NZ]

What exactly is the difference between SN1 and SN2 reaction mechanisms?

[Mr Skeptic]

In SN1 the slow step involves 1 molecule, in SN2 the slow step involves 2 molecules. Both are SubstitutioN reactions.

[Horza2002]

The rate determining step of a SN1 only has one molecule (this is usually a group falling off the molecule). For an SN2, the rate determining step involves two molecules (the electrophile and nucleophile normally)