you need
  • school textbooks in chemistry class 8-9 or any author, periodic table, the table electronegativity elements (printed in textbooks in chemistry).
Guide
1
First we need to indicate that the degree of oxidation
- this concept conditional receiving communication of ion that is not to go into the building.If the item is in a free state, it is the most simple case - a simple substance is formed, and thus the degree of oxidation it is zero.Thus, for example, hydrogen, oxygen, nitrogen, fluorine, etc.
2
In complex materials are quite different: the electrons between atoms are unevenly distributed, and that the degree of oxidation helps determine the number of electrons given or received. degree of oxidation can positive and negative.When the electrons are given to the black, with red, please.Some elements of their degree of oxidation stored in various compounds, but many of the features are not different.It should be remembered not least a rule - the sum of the degrees of oxidation always zero.The simplest example, CO gas: knowing that the degree of oxidation oxygen in the majority of cases is equal to -2 and using vysheoboznachennyh usually possible to calculate the degree of oxidation for carbon C. The amount of zero to -2 gives only two, and thus the degree of carbon oxidation 2.Complicate the problem and take the CO2 gas for calculations: the degree of oxidation oxygen remains -2, but its molecules, in this case two.Consequently, (-2) * 2 = (-4).The number, plus the zero giving -4, +4, i.e. the gas has a carbon +4 oxidation.An example of a little more complicated: H2SO4 - from hydrogen oxidation degree +1, -2 from oxygen.Taken in conjunction two molecules of hydrogen and 4 of oxygen, i.e.charges will be respectively 2 and -8.In order to receive a total of zero, add 6 plus.Thus, the degree of oxidation sulfur 6.
3
When the compound is difficult to determine where the plus, minus where necessary electronegativity table (it is easy to find in a textbook of general chemistry).Metals often have a positive degree of oxidation , and negative non-metals.But for example, PI3 - both elements nonmetals.The table shows that the electronegativity of iodine is 2.6 and P 2.2.When comparing it turns out that 2.6 is greater than 2.2, that is, the electrons are pulled together in the direction of iodine (iodine has a negative power oxidation ).By following simple example, you can easily determine the degree of oxidation any element in the compounds.