Electrochemistry/Redox

• Oxidation Numbers: a number given to each atom in a compound to keep track of how many electrons they have
• Positive Oxidation #: loss of electrons
• Negative Oxidation #: gain of electrons
• The oxidation number of any uncombined element is 0
• Group 1 elements are always +1
• Group 2 elements are always +2
• Flourine is always -1
• Hydrogen is +1 with nonmetals and -1 with metals
• Oxygen is -2, -1 in hydrogen peroxide and +2 in F20
• The oxidation # of a monatomic ion is the ion charge
• The sum of the oxidation # in a compound is 0
• The sum of oxidation # in an ion is equal to the charge of the ion
• Halogens: usually -1, positive with oxygen
• Redox reactions: reactions in which oxidation and reduction take together
• Disproportionation Reaction: a reaction in which the same species is both oxidized and reduced