Oxidation/Reduction Reactions

Oxygen is a highly abundant element on the planet Earth. Composing over 20% of the atmosphere and over 40% in the Earth’s crust, oxygen is readily available to make compounds with most of the other elements. Oxidation and reduction reactions were first defined by the addition or subtraction of oxygen from a reaction. The definition was eventually changed to include similar reactions that do not involve the element oxygen. In this topic, you will investigate oxidation-reduction reactions. These reactions, also known as redox reactions, always involve a gain and loss of electrons.

Essential Questions

• How can oxidation and reduction be described in terms of a gain or loss of electrons?
• How does oxidation and reduction occur in ionic and molecular reactions?