You assign oxidation numbers to the elements in a compound by using the Rules for Oxidation Numbers.

Explanation:
1.The oxidation number of a free element is always 0.

2.The oxidation number of a monoatomic ion equals the charge of the ion.

3.The oxidation number of
H is +1, but it is -1 in when combined with less electronegative elements.

4 The oxidation number of
Oin compounds is usually -2, but it is -1 in peroxides.

5. The oxidation number of a Group 1 element in a compound is +1.

6.The oxidation number of a Group 2 element in a compound is +2.

7.The oxidation number of a Group 17 element in a binary compound is -1.

8.The sum of the oxidation numbers of all of the atoms in a neutral compound is 0.

9.The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

Finding Oxidation States

Oxidation states are the charges on the atoms in a compound, assuming that the electrons are shared as equally as possible between the atoms. Here are the steps to find oxidation states:

1. Determine the charge of the molecule or polyatomic ion
The sum of the oxidation states in a molecule or polyatomic ion must equal the charge of the molecule or ion. For example, in H2SO4, the charge is -2 (since it is a polyatomic ion with a charge of -2), so the sum of the oxidation states must be -2.

2. Determine the oxidation state of the most electronegative atom
The most electronegative atom in a molecule or ion (usually oxygen or fluorine) is assigned a negative oxidation state. For example, in H2SO4, oxygen has an oxidation state of -2.

3. Determine the oxidation state of hydrogen
Hydrogen is assigned a +1 oxidation state when bonded to a nonmetal and a -1 oxidation state when bonded to a metal. For example, in H2SO4, hydrogen has an oxidation state of +1.

4. Determine the oxidation state of the remaining atoms
Use the charge of the molecule or polyatomic ion and the oxidation states of the other atoms to determine the oxidation state of the remaining atoms. For example, in H2SO4, sulfur has an oxidation state of +6.

5. Check your work
Make sure the sum of the oxidation states equals the charge of the molecule or polyatomic ion.

Conclusion

In conclusion, determining oxidation states is an important step in balancing equations and understanding chemical reactions. By following these steps, you can determine the oxidation state of each atom in a molecule or ion and use this information to predict the outcome of a reaction.