Oxidation Numbers
Definition
Oxidation number, also called oxidation state, is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom
Rules
[!rules]
todo rules with groups
Rules
- The oxidation number of any uncombined element or element in a diatomic gas is a zero
in
- The oxidation number of any monatomic ion is equal to its charge
in in
- In ionic compounds, the sum of the oxidation numbers of the elements in a compound or ion must equal the overall charge
- In covalent compounds with no
or : treat like an ionic compound. The more electronegative element assumes a charge equal to what it would be in an ionic compound in in
Other Rules
| Element | Oxidation Number | Exceptions |
|---|---|---|
| None | ||
| In compounds with |
||
| In metal hydrides (-1) or if it's in an ionic compound | ||
| Group 1 metals | None | |
| Group 2 metals | None |
Examples
- What is the oxidation number of
? - 0
- What is the oxidation state of
in ? - +2
- What is the oxidation number of
in ? - +4 since
- +4 since
- What is the oxidation state of
in - +6 since
- +6 since
- What is the oxidation number of carbon in the carbonate ion,
- +4, since the whole ion has charge -2, and
- +4, since the whole ion has charge -2, and
Exceptions to the rules
todo