Oxidation and Reduction

Oxidation and Reduction:

• Understand the definition of oxidation as the loss of electrons and reduction as the gain of electrons.

• Familiarize yourself with the term “redox reaction”, which is a chemical process that involves both oxidation and reduction.

• Learn the mnemonic “OIL RIG” to remember the definitions: Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).

• Hone the ability to identify the oxidation state of an atom in a molecule or ion: the oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic.

• Note that elements with uncombined atoms have an oxidation state of zero.

• Realize that in their compounds, Group 1 elements have an oxidation state of +1 whilst Group 2 elements have an oxidation state of +2. Also, fluorine always has an oxidation state of -1.

• Remember that the sum of the oxidation states in a neutral compound is zero, and in an ion it is equal to the charge of the ion.

• Recognise how to assign oxidation states to atoms in chemical equations, realise when an atom is being oxidised or reduced and thereby identify the oxidising and reducing agents.

• Understand the concept of half-equations and their role in balancing redox reactions. A half-equation represents either the oxidation or reduction process separately and includes electrons to balance the charges.

• Get familiar with the various practical applications of redox reactions such as in batteries, fuel cells, the extraction of metals from their ores, etc.

• Practise conducting calculations involving redox reactions; this will typically involve using the concept of moles and the stoicheiometry of the reaction.

• Lastly, appreciate that redox reactions are prevalent in numerous biological systems and environmental processes.