how do you assign oxidation numbers t o an element? i know u se the periodaic table but i don't know how to find the number

A set of rules to help you get started.

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Assigning oxidation numbers to an element involves a set of rules. Here's a step-by-step guide on how to determine oxidation numbers:

1. Oxidation numbers are assigned assuming that the compound is ionic, so start by looking at the elemental symbol on the periodic table.

2. Group 1 elements (alkali metals) always have an oxidation number of +1. Group 2 elements (alkaline earth metals) always have an oxidation number of +2.

3. In compounds, oxygen is generally assigned an oxidation number of -2. Exceptions to this rule include compounds like peroxides (O2^-2) and superoxides (O2^-).

4. Hydrogen is typically assigned an oxidation number of +1, except in hydrides (-1 when combined with less electronegative elements) or compounds like metal hydrides (where oxidation number is -1).

5. The sum of all oxidation numbers in a neutral compound is zero, and the sum in a polyatomic ion equals the charge of the ion. Use this information to determine other oxidation numbers.

6. For elements in the middle of the periodic table (transition metals), oxidation numbers can vary. Determine these numbers based on other known oxidation states or through the chemical equation context.

7. Polyatomic ions have fixed oxidation numbers for each element within them. You can find the oxidation numbers for common polyatomic ions in chemistry reference materials or online resources.

8. Lastly, remember that oxidation numbers are not actual charges; they are just hypothetical values used for bookkeeping and determining oxidation-reduction reactions.

By following these steps and considering specific rules for certain elements or compounds, you should be able to assign oxidation numbers successfully.

To assign oxidation numbers to an element, you generally follow a set of rules. Here are the steps to determine the oxidation number of an element:

1. Start with the most electronegative atom in the compound. In most cases, it will be the atom with the highest electronegativity value on the periodic table.

2. Determine the known oxidation numbers of other elements in the compound. Common elements with fixed oxidation numbers include hydrogen (+1) and oxygen (-2).

3. If the compound is neutral, the sum of all oxidation numbers should be zero. If the compound is an ion, the sum of all oxidation numbers should equal the charge of the ion.

4. When assigning oxidation numbers, consider the general guidelines:

a. In covalent compounds, atoms usually possess their characteristic oxidation numbers, except for hydrogen and oxygen.

b. Hydrogen usually has an oxidation number of +1, except when it is combined with a metal, where it has an oxidation number of -1.

c. Oxygen usually has an oxidation number of -2, except in peroxides where it has an oxidation number of -1.

d. Group 1 elements have an oxidation number of +1, and Group 2 elements have an oxidation number of +2.

e. Fluorine always has an oxidation number of -1, while other halogens (- Group 7 elements) usually have an oxidation number of -1 as well, except when they are combined with more electronegative elements.

f. The sum of all oxidation numbers in a neutral compound is zero.

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

By applying these general rules, you can determine the oxidation number of an element in a compound.