oxidation number rules

oxidation number rules - atom is assigned the negative...

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Rules for Assigning Oxidation Numbers Elements (1) The oxidation number of an atom in a free element is zero (i.e., Na, N 2 ). Compounds (2) Hydrogen is +1. Exception: H is 1, when combined with a metal (i.e., MH x ). (3) Oxygen is 2. Exception: Oxygen is 1 in peroxides; anion = O 2 2 . (i.e., H 2 O 2 , K 2 O 2 , BaO 2 ) (4) The oxidation number of metals is positive: Group 1: +1 Group 2: +2 Group 13: +3 (5) The oxidation number of nonmetals is always negative when combined with a metal : Group 17: 1 Group 16: 2 Group 15: 3 When combined with another nonmetal , (molecular compound), the more electronegative
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Unformatted text preview: atom is assigned the negative oxidation number. NF 3 : N: Electronegativity = 3.04 would be assigned +3 F: Electronegativity = 3.98 would be assigned 1 (6) The oxidation number of a monoatomic ion is equal to the charge on the ion. Na + : +1 Cl : 1 Ba 2+ : +2 S 2 : 2 Al 3+ : +3 (7) The sum of the oxidation numbers of the atoms in a polyatomic ion must equal the charge of the ion. NO 3 : (1)(+5) + (3)( 2) = 1 (8) The sum of the oxidation numbers of the atoms in a compound must equal zero. BaCl 2 : (1)(+2) + (2)( 1) = 0...
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