Final answer:
Oxidation is when an element goes from having more to fewer valence electrons, symbolizing the loss of electrons, while reduction is the gain of electrons. These processes are part of redox reactions, where one substance gets oxidized and another gets reduced.
Step-by-step explanation:
Oxidation and Reduction in Redox Reactions
When discussing a chemical reaction where an element goes from having more valence electrons to fewer valence electrons, we refer to this process as oxidation. Conversely, reduction refers to an element gaining electrons, resulting in a decrease in its oxidation number. In any electrochemical process, such as a redox reaction, electrons flow from the substance being oxidized to the one being reduced. An easy way to remember this is through the mnemonic OIL RIG, which stands for "Oxidation Is Loss, Reduction Is Gain" of electrons.
Oxidation and reduction reactions are always coupled and together are called redox reactions. The substance that donates electrons is the reductant, and the substance that accepts electrons is the oxidant. The flow of electrons from one species to another is driven by the potential energy difference between their respective valence electrons.