Conduction
Definition and meaning of Conduction in chemistry.
Conduction is the transfer of heat or electric charge through a material by direct particle-to-particle interaction, without any net bulk movement of the material itself. It occurs as thermal conduction (energy transfer) or electrical conduction (charge transfer).
In more detail
In thermal conduction, energy passes from hotter to cooler regions through collisions between vibrating atoms or molecules and, in metals, through mobile electrons that carry energy efficiently. In electrical conduction, charge carriers move under an applied electric field: electrons drift through metals and semiconductors (electronic conduction), while ions migrate through molten salts or electrolyte solutions (ionic or electrolytic conduction). Conductivity depends on how many charge carriers are available and how freely they can move, which is why metals conduct electricity far better than pure covalent liquids or solids with rigidly bound ions.
Key facts
| Field | Physical Chemistry |
|---|---|
| Main types | Thermal conduction; electronic conduction; ionic (electrolytic) conduction |
| Charge carriers | Electrons (metals/semiconductors) or ions (electrolytes, molten salts) |
| SI unit of electrical conductivity | Siemens per meter (S/m) |
Molten sodium chloride (NaCl) conducts electricity because its Na⁺ and Cl⁻ ions are free to migrate toward the electrodes, whereas solid NaCl does not conduct, since its ions are locked in a fixed crystal lattice and cannot move.
Frequently asked questions
What is the difference between electronic and ionic conduction?
Electronic conduction is charge transport by electrons, as seen in metals and semiconductors, and does not require the material itself to move. Ionic conduction is charge transport by the physical migration of ions through a molten salt or electrolyte solution.
Why does pure water conduct electricity poorly?
Pure water contains very few ions, produced only by its slight self-ionization into H3O+ and OH-, so it has very low electrical conductivity; dissolving an electrolyte adds mobile ions that greatly increase conductivity.