## Oxidation Number

Daniel Yu 1E
Posts: 100
Joined: Sat Aug 24, 2019 12:15 am

### Oxidation Number

What is an oxidation number and how is it calculated? Is it just the charge of the molecule as an anion?

Shimei_2F
Posts: 100
Joined: Fri Aug 09, 2019 12:17 am

### Re: Oxidation Number

The oxidation number of an atom is the charge that an atom would have if the compound was composed of ions. The oxidation number of each atom can be calculated by subtracting the sum of lone pairs and electrons it gains from bonds from the number of valence electrons.

Anna Chen 1K
Posts: 104
Joined: Thu Jul 25, 2019 12:18 am

### Re: Oxidation Number

An oxidation number is the charge that atom would have if it was made up of ions.

Daniel Yu 1E
Posts: 100
Joined: Sat Aug 24, 2019 12:15 am

### Re: Oxidation Number

So does this mean that the oxidation number is basically the sum of the formal charges of all atoms within a molecule?

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

### Re: Oxidation Number

Oxidation number is based on the number of electrons an atom in ground state gains or loses. Depending on an atom's ionization energy and electron affinity, they are either found as cations or anions.

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

### Re: Oxidation Number

Yes, the oxidation number of a molecule would be the sum of the formal charges.

Hannah Pham
Posts: 104
Joined: Fri Aug 09, 2019 12:17 am

### Re: Oxidation Number

The oxidation number is the number of electrons that an atom gains or loses in order to form a chemical bond with another atom. It shows the total number of electrons that have been removed from an element (positive oxidation state) or added to an element (negative oxidation state) to get to its present state.
The rules are:
-The oxidation number of a free element is always 0.
-The oxidation number of a monatomic ion equals the charge of the ion.
-The oxidation number of H is +1, but it is -1 in when combined with less electronegative elements.
-The oxidation number of O in compounds is usually -2, but it is -1 in peroxides.
-The oxidation number of a Group 1 element in a compound is +1.
-The oxidation number of a Group 2 element in a compound is +2.
-The oxidation number of a Group 17 element in a binary compound is -1.
-The sum of the oxidation numbers of all of the atoms in a neutral compound is 0.
-The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.