The chemical properties of organic molecules are determined by specific arrangements of atoms called .

Functional group

Explanation:

Functional group is specific group of atom or bond associated to an organic compound that determines the chemical properties of that compound. This atom is bonded in a certain way or specific arrangement to give the compound a peculiar physical and chemical characteristics.

Functional group like the alkyl group -CH3 is found in organic compound series like the alkane family. The chemical properties specific to the alkyl group will be active in the compound of alkane family because of the presence of the functional group Alkyl(-CH3).  The functional group also plays a major role in the chemical  reactivity of the compound. For example the functional group of alkyl  are often non reactive, this non reactive nature will definitely rub off on the chemical properties of the compound it is attached.

Functional group like -OH is usually found in Alcohol . Due to the presence of this functional group (-OH) alcohol possess a peculiar chemical properties. The compounds possess an hydrogen bond which invariably lead to the higher boiling points of the alcohol compounds.  Other functional group can be bonds like double bond found in alkene compound or triple  bond found in alkyne compound.