How To Calculate Oxidation Numbers - Basic Introduction

Basic Rules for Elements and Ions00:00:01

Pure elements always have an oxidation state of zero. Monoatomic ions have oxidation states equal to their charge. Diatomic or multi-atom ions require setting up an equation to find the individual oxidation state, dividing the net charge by the number of atoms.

Rules for Compounds and Electronegativity00:02:56

Fluorine is always -1. Oxygen is typically -2, except in peroxides (-1) and superoxides (-0.5). Hydrogen is +1 when bonded to non-metals and -1 when bonded to metals. Electronegativity determines which element carries the partial negative charge; the more electronegative element is usually assigned its standard periodic table oxidation state.

Examples with Compounds and Polyatomic Ions00:04:23

Practical walk-throughs on calculating oxidation states for compounds like magnesium chloride, vanadium oxide, and polyatomic ions like sulfate, phosphate, and nitrate using algebraic equations.

Handling Decimal Oxidation States00:21:13

Explanation of why some compounds (like Fe3O4) result in decimal oxidation states, representing an average when multiple atoms of the same element exist in different oxidation states within the same structure.

Complex Examples and Electronegativity Comparisons00:24:22

Advanced examples including compounds with three elements, such as potassium chromate and potassium bicarbonate, and using electronegativity values to identify which halogen in interhalogen compounds carries the negative charge.