Small groups of atoms that are attached to larger molecules, giving the specific chemical properties, are called

Small groups of atoms that are attached to larger molecules, giving the specific chemical properties, are called functional groups.

Functional groups are groups of atoms in a molecule that possess the same chemical feature every time it appears in several compounds. There are various types of functional groups and they have the tendency to react in definite ways. Examples include; the ether functional group (consists of an oxygen atom that forms single bonds with two carbon atoms),the alcohol functional group (consists of an oxygen atom that is bonded to one hydrogen atom and one carbon atom), and the amine functional group (consists of a nitrogen atom bonded to some combination of carbons and hydrogens).