Oxidation Number

Oxidation Number

• A number assigned to an atom that represents the charge the atom would have if all bonding electrons were assigned to the more electronegative atom.

• A bookkeeping value used to track electron transfer in chemical compounds and reactions.

Zero

The oxidation number of an atom in an elemental substance is always

Ion’s charge

The oxidation number of a monatomic ion is equal to the

+1

Oxidation Number of Hydrogen when combined with a nonmetal

-1

Oxidation Number of Hydrogen when combined with a metal

-2

Oxidation Number of Oxygen in most compounds

-1

Oxidation Number of Oxygen in peroxides

-0.5

Oxidation Number of Oxygen in most superoxides

fluorine

Oxygen only has a positive oxidation number when combined with ________

Peroxide Ion

O₂²⁻

Superoxide Ion

O₂⁻

-1

Oxidation Number of Fluorine or the Fluorine in its compounds

Fluorine, Chlorine, Bromine, Iodine, Astatine, and Tennessine

Name all the halogen elements in order

-1

Oxidation number of Halogens

Chlorine, Bromine, and Iodine

Name the three halogen elements, where when they are combined with the Oxygen or other halogen, they have a positive oxidation number

Sum Rule for Oxidation Numbers

The sum of the oxidation numbers of all atoms in a molecule or polyatomic ion equals the overall charge of the molecule or ion.

zero

Oxidation Number Sum in a Neutral Molecule is ____

ion’s charge

Oxidation Number Sum in a Polyatomic Ion equals the ___________

Oxidation Number Notation

• Oxidation numbers are written with the sign first, then the number

• Examples: +2, -1, +5

Ionic charge

Represents the actual electrical charge