Oxidation Numbers & Redox Reactions Worksheet +Key

Oxidation numbers look like memorization until a compound breaks every rule — then students need to actually solve for the answer. This worksheet builds that algebraic skill first, then applies it to the real question oxidation numbers exist to answer: is this reaction a redox reaction?

✅ Clear explanation of oxidation numbers and the full rule set (Group 1A/2A, halogens, hydrogen, oxygen, fluorine, ions, and neutral compounds)
✅ Step-by-step explanation of the algebraic method for elements with no fixed rule, plus a fully worked example
✅ Part 1: Assigning Oxidation Numbers — 20 compounds and ions with the target element underlined, covering every rule including tricky exceptions like peroxides and OF₂
✅ Part 2: Identifying Redox Reactions — a full explanation of oxidation vs. reduction, both classic mnemonics (OIL RIG and LEO the lion says GER), a worked example, and 10 reactions to balance, assign oxidation numbers to, and classify
✅ Problems are a genuine mix — 7 redox reactions and 3 non-redox reactions, so students have to actually determine which is which instead of assuming every problem needs the full oxidized/reduced/agent breakdown
✅ For every redox reaction: identify the element oxidized, element reduced, oxidizing agent, and reducing agent
✅ Generous work space for every problem
✅ Full answer key with every oxidation number, balanced equation, and redox classification shown
✅ Instant digital download (PDF)