Chemical properties of nanomaterials also change at nanoscale. As the percentage of surface atoms in nanoparticles is large compared with bulk objects, therefore reactivities of nanomaterials are more than bulk materials. The following are the some of the chemical properties are:

1.) The preponderance of surface is a major reason for the change in behaviour of materials at the nanoscale. As up to half of all the atoms in nanoparticles are surface atoms, properties such as electrical transport are no longer determined by solid-state bulk phenomenon.

2.) The atoms in nanomaterials have a higher average energy than atoms in longer structures, because of the larger proportion of surface atoms. For example, catalytic materials have a greater chemical activity per atom of exposed surface as the catalyst is reduced in size at the nanoscale.

3.) Defects and impurities may be attracted to surfaces and interfaces, and interactions between particles at those small dimensions can depend on the structure and nature of chemical bonding at the surface.

4.) Molecular monolayers may be used to change or control surface properties and to mediate the interaction between nanoparticles.