Oxidation Numbers are numbers assigned to each atom in order to keep track of the movement electrons during a chemical reaction. In other words, an oxidation number is defined as the atom's apparent electrical charge according to a specific set of rules for assigning these numbers. Before detailing the rules, it is important to make one important point: except for monatomic ions, the oxidation number for an atom does not represent its actual electric charge, but merely represent a way of identifying oxidation-reduction reactions.
Recognizing oxidation-reduction reactions is beyond the scope of this module. Rather, the objective here is learning the method by which oxidation numbers are calculated. The method for calculating oxidation numbers is one of the most useful tools chemists have for understanding reactivity.
INSTRUCTIONS
1. Select an Element, either Carbon, Nitrogen, Sulfur, Phosphorus,
Vanadium, or Lead. To change your choice, simply click on
another Element option button.
2. Using the spinbuttons, vary the number of hydrogen, oxygen,
and central atoms, and vary the charge on the molecule or ion
using the charge spinbutton. The program will calculate and
display the oxidation numbers for each atom. Record all
oxidation numbers and the charge for each example; this will be
useful in your attempt to understand how oxidation numbers are
assigned or calculated. Many of the examples you can examine
in this module are compounds or ions that are not stable in nature.
You should keep in mind that while an oxidation number can be
calculated for these species, you will not encounter them in routine
chemical investigations. A disclaimer appears if the molecule you
have designed is unstable.
3. Select Summary to review the rules for assigning oxidation numbers.
4. Once in the Summary sections, to return to the main exercises select
Return to Oxidation Number Exercises. To exit, simply click on
