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Oxidation numbers (states)
CHEMISTRY - Secondary 2
In This part we will study:
 Metallic and nonmetallic property:
Oxidation number: is a number that refers to the electric charge (positive or negative) that the atom or ion would have in the compound, whether it is an ionic or a covalent compound.
The significance of oxidation numbers:
The significance of oxidation numbers differs in ionic compounds from that of the covalent compounds.

Rules for calculating the oxidation numbers
How to assign the oxidation number of an unknown element in a given compound or atomic group
Calculating the change of the oxidation number in the oxidation-reduction Reaction (redox reaction)
The advantage of using oxidation numbers is that they can help us in determining the type of chemical change occurring to an element during the chemical reaction.
You already know the concepts of the oxidation and reduction, which are:
Oxidation is the process of losing electrons resulting in an increase of the positive charge.
Reduction is the process of gaining electrons resulting in a decrease of the positive charge.

So, we can determine the changes happen to the elements during the oxidation-reduction reactions through the change in their oxidation numbers (states) before and after the reaction, where:
• The reducing agent (metal) is oxidized.
• The oxidizing agent (nonmetal) is reduced .

Best wishes to you
Mr.Ahmed Elbasha

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