OXIDATION NUMBERS Section 22.2
Assigning Oxidation Numbers A positive or negative number assigned to an atom according to the following rules: 1. The oxidation number for a monatomic ion is equal to its ionic charge 2. The oxidation number of hydrogen is +1, except for metal hydrides, where it is The oxidation number of oxygen is -2, except in peroxides, where it is The oxidation number of an atom in uncombined form is 0 5. For any neutral compound, the sum of the oxidation numbers must equal 0 6. For a polyatomic ion, the sum of the oxidation numbers must equal the ionic charge of the ion
What is the oxidation numbers of each kind of atom in the following compounds? SO 2 CO 3 2- K 2 SO 4
Let’s try it! 2AgNO 3(aq) + Cu (s) Cu(NO 3 ) 2(aq) + 2Ag (s) 1. Find the oxidation number of each atom AgNO 3(aq) + Cu (s) Cu(NO 3 ) 2(aq) + 2Ag (s) 2. Which atom is being oxidized? Copper ~ Cu (s) Cu +2 (aq) 3. Which atom is being reduced? Silver ~ Ag + (aq) Ag (s)