Answer:
Nucleophilic reaction
and
Step-by-step explanation:
A nucleophilic reaction is a type of reaction that involves attack of a specie having a negative charge or a lone pair of electrons on a positive center. This negatively charged specie or specie having a lone pair of electrons is called a nucleophile.
An SN2 reaction is a bimolecular, concerted nucleophilic reaction that leads to inversion of configuration at the carbon center. The leaving group is the group that departs from the frontside of the molecule as the nucleophile attacks from the backside.