4th Class Power Engineering Steam Practice Test 2026 - Free Practice Questions and Study Guide

Corrosion caused by electrolysis happens when the metal atoms lose electrons in an oxidation process. Those electrons travel through the external circuit to the other electrode, while the metal atoms become positively charged ions that can go into solution. Protons and neutrons stay in the atomic nucleus and don’t participate in this transfer, so they aren’t the particles being lost. Ions in solution are formed as a result of the metal losing electrons, but the actual particle lost from the metal is the electron itself.