adsorption

Adsorption is the adhesion of the atoms or molecules of a substance to the surface of a solid or liquid. (The "ad" is for "adherence" or "adhesion".) The substance attached to the surface can be gas, liquid, or dissolved solid. Two classes of adsorption are:

• physisorption - adsorption not involving chemical bonding or reconfiguration, generally caused by a van der Waals force, which is weak a type of force between molecules, that can draw them together without reconfiguring them into different molecules.
• chemisorption - adsorption that does involve a chemical reaction between the components, i.e., formation of new molecules through covalent or ionic bonds, i.e., sharing or transferring electrons.