1.7 Oxidation, reduction and redox equations

What is oxidation?

Oxidation is the process of electron loss.

What are oxidising agents?

Oxidising agents are electron acceptors.

What is reduction?

Reduction is the process of electron gain.

What are reducing agents?

Reducing agents are electron donors.

What is the oxidation state of an element?

The oxidation state is a number representing the number of electrons an element has donated or accepted.

What is the oxidation state of an uncombined element, such as He and Ar?

The oxidation state of an uncombined element is 0.

What is the oxidation state of an element bonded to identical atoms, such as O2 and H2?

The oxidation state of an element bonded to identical atoms is 0.

What is the oxidation state of a simple monatomic ion, such as Na+?

The oxidation state of a simple monatomic ion is equal to the ion's charge.

What is the overall oxidation state of a compound ion?

The overall oxidation state of a compound ion is equal to the ion's charge.

The charge is equal to the sum of the individual oxidation states of all the elements.

What is the oxidation state for combined group 1 elements?

The oxidation state for combined group 1 elements is always +1.

What is the oxidation state for combined group 2 elements?

The oxidation state for combined group 2 elements is always +2.

What is the oxidation state for combined hydrogen?

The oxidation state for combined hydrogen is +1 in compounds with non-metals, however it is -1 in metal hydrides.

What is the oxidation state for combined fluorine?

The oxidation state for combined fluorine is always -1.

What is the oxidation state for combined oxygen?

The oxidation state for combined oxygen is -2, except for in peroxides, where it is -1. This takes other values when bonded to fluorine.

What is the oxidation state for combined chlorine?

The oxidation state for combined chlorine is -1, however this takes other values when bonded to fluorine and oxygen.

What do half equations show?

Half equations show the oxidation or reduction of a species.
They also show the electrons which are being lost or gained.