Hi, The formula of caffeine is C8H10N4O2. The oxidation numbers of O & H are -2 & +1 according to the book. How do I determine the oxidation numbers of C or N. Note: The substance is a molecular substance so we cannot apply the following rule: "the oxidation number of an atom in a monatomic ion is the charge of the monatomic ion" How do I determine the oxidation numbers of C or N? Can someone please help me out? Thanks in advance!!