Chapter 4. Balancing Oxidation Reduction Reactions Van Koppen Chem. 1A F05 Simple Conventions to Assign Oxidation States: 1) The oxidation numbers of the atoms in a neutral molecule must add up to zero, and those in an ion must add up to the charge on the ion. All elements have oxidation states of zero (e.g. Na(s), O 2 (g), H 2 (g), Cl 2 (g), etc.) 2) Alkali metal atoms (Group I) have oxidation number +1 in their compounds, and alkaline earth atoms (Group II) have oxidation number +2 in their compounds. 3) Fluorine always has an oxidation number of –1 in its compounds, and other halogens have an oxidation number –1 in their compounds except in compounds with oxygen and with other halogens, where they can have positive oxidation numbers. ClO – NaCl SF 6 (Each fluorine in SF 6 is assigned an oxidation state of –1.) + 1 – 2 + 1 – 1 + 6 – 1 4) Hydrogen is assigned an oxidation number of +1 in its compounds, except metal hydrides such as LiH where convention 2 takes precedence and hydrogen has an oxidation number –1. H
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This note was uploaded on 04/24/2011 for the course CHEM 1A taught by Professor Van koppen during the Fall '07 term at UCSB.