Oxidation Number Lab Report

Oxidation number, also known as oxidation states, is used for determining how many electrons an atom has. However, oxidation numbers do not necessarily mean real charges of on molecules. Therefore, we can determine oxidation numbers for atoms of any element irrespective of covalent or ionic bonding. Let us go through the article to understand oxidation numbers in details!!

Oxidation Number

One of the less known examples of electron transfer is when hydrogen and oxygen combine to form water. All of us know the reaction Even though it is not a very common reaction but we can notice that the H atom in the neutral state (zero) in H2 converts to positive state after the formation of H2O. Similarly, the oxygen atom in O2 is present in its zero

The rules were set on the basis of the electron pair of a covalent compound and the electronegativity of an element. However, it is difficult to make out which is more electronegative element than the other in any given compound or ion. Thus, it led to the formulation of a certain set of rules for the determination of an element in a particular compound or ion. Moreover, if in a molecule/compound/ion two or more elements are present then the average of all the atoms of the particular element is taken to find the oxidation number of the given element. We will further understand this later with an example.

Rules for Determination of Oxidation Number:

Rule 1

When the elements are present in free or its elemental state then the oxidation number of the particular element will be zero. Therefore, each atom in H2, O2, Na, Cl2, O3, P4, S8, Mg, etc in their free form has oxidation number zero.

Rule 2

Ions having one atom bear oxidation number equal to the charge present on the ion. For instance, Na+ ion has oxidation the oxidation number +1. Similarly, Mg2+, Fe3+ ion, Cl– ion, O2– ion will have charge +2, +3, –1, –2, respectively. This rule will apply to all ions. All alkali metals in the compound form will have oxidation number +1. Similarly, all alkaline earth metals have an oxidation number of +2. However, aluminum in all its compound form has oxidation number

However, there are exceptions in case of peroxides, superoxides, and oxygen bonded with fluorine. Superoxides and Peroxides are compound of oxygen in which atoms of oxygen are linked directly to one another. In the case of peroxides such as H2O2, Na2O2 has oxidation number -1 whereas in the case of superoxides KO2, RbO2 each oxygen atom will have the oxidation number of –(½). The second exception is a rare case. Oxygen forms bond with fluorine forming compounds such as oxygen difluoride and dioxygen difluoride. The oxidation number of oxygen difluoride (OF2) is +2. The oxidation number of dioxygen difluoride (O2F2) is +1. The changes in oxidation number occur due to the bonding state of oxygen.

Rule 4

Usually, hydrogen bears the oxidation number +1. However, there are exceptions in the case when hydrogen bonds to metals in the case of binary compounds or compounds that contain two elements in a single compound. For instance, NaH, CaH2, LiH. In all the examples the oxidation state of hydrogen is -1.

Rule