What Is Oxidation

Part of the Oxidation and Reduction section of Coddy's Chemistry journey. Lesson 1 of 27.

In 2Na + Cl₂ → 2NaCl each sodium atom gives an electron to a chlorine atom.

A sodium atom with shells 2, 8, 1 beside a sodium ion with shells 2, 8: the outer electron is gone

Sodium is oxidized: it loses its outer electron

Oxidation is losing electrons; reduction is gaining them. Sodium is oxidized, chlorine is reduced.

A chlorine atom with shells 2, 8, 7 beside a chloride ion with shells 2, 8, 8

Chlorine is reduced: it gains an electron

One cannot happen without the other: the electrons lost are the electrons gained. Remember OIL RIG: oxidation is loss, reduction is gain.

Challenge

Sodium metal reacts with chlorine gas to make table salt. Which element is oxidized, and which is reduced?

Try it yourself

Oxidation numbersFollow the electrons

NaCl₂NaCl

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Oxidation and Reduction

1Electron Transfer

4Metals and Reactivity

2Redox Reactions

5Electrochemistry

3Half-Equations

6Practice Problems