Document page
chemistry igcse acapprinted 28 · PDF 28
145 pagesrevision 46934
printed 28 · PDF 28
Page image rendered from the stored file at 110 dpi; it sharpens as you zoom. Outlines are placed from each region’s stored position on the page (612 × 792 pt).
readable
Source of this text: embedded text layer. The better of the embedded text and OCR is kept.
28
Ionic Equations
Electrolysis is characterized by electron transfer.
Oxidation occurs at the anode (electron loss).
Reduction occurs at the cathode (electron gain).
Example: Electrolysis of water splits it into hydrogen and oxygen gases.
At the Cathode: H⁺ + e⁻ → H₂(g)
At the Anode: 2H₂O(l) → O₂(g) + 4H⁺ + 4e⁻
Metals:
All metallic ions are positively charged. If the metal is being produced during electrolysis, it will
gain electrons to form the metal’s atoms as the metal ions are being reduced. Number of electrons
gained by a metal is determined by the charge value on the metal’s ions. Following are a few
examples:
Non-Metals:
All non-metallic ions are negatively charged. If a non-metal is produced during electrolysis, it will
lose electrons to form non-metallic atoms as the non-metal ions are being reduced. Number of lost
electrons corresponds to the charge on the non-metallic ion. Following is an example: