What type of reaction is it when one of more atoms replace one other atom or group of atoms in a molecule?

The reaction in which one or more atoms replace another atom or group of atoms in a molecule is called a substitution reaction. This type of reaction is common in organic chemistry and can involve various mechanisms, such as nucleophilic substitution or electrophilic substitution. During this process, the original atom or group is displaced, leading to the formation of a new compound.