Rules for Oxidation Numbers
Part of the Oxidation and Reduction section of Coddy's Chemistry journey. Lesson 3 of 27.
Go down the rules: F −1; group 1 +1, group 2 +2, Al +3; H +1 (−1 in a metal hydride).
O is −2, except in a peroxide (−1) and beside F. A halogen is −1 when it pulls hardest.
The last element comes from the sum. In KMnO₄: (+1) + Mn + 4(−2) = 0, so Mn is +7.
Challenge
Potassium permanganate, KMnO₄, is a purple disinfectant. Give each element its oxidation number.
Try it yourself
Oxidation numbersGive the oxidation numbers in KMnO4
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Oxidation and Reduction
1Electron Transfer
What Is OxidationOxidation NumbersRules for Oxidation NumbersOxidation Numbers in IonsRecap - Number Painter