Oxidation number

Question

 how to find oxidation no. of central atom in a complex??

Answer 1

The oxidation number is an indicator of the degree of oxidation. Conceptually it is a hypothetical number or charge that an atom would have if all bonds were purely ionic, as in not covalently attached. NOTE: Atoms in their elemental forms will NOT have an oxidation number. Examples of elemental forms: Cl₂, O₂, Al(s)...

 

Oxidation number Example:

 

NaCl

Purely Ionic = Na⁺ + Cl^-

Na = +1 oxidation number

Cl = -1 oxidation number

 

example:

 

AlCl₃

Purely ionic = Al^-3 + 3Cl^-

We know charges balance, Cl has a -1 charge and there are 3 of them attached to Aluminum so...

 

Al = +3 oxidation number

Cl = -1 oxidation number

 

Example of metal with multiple oxidation states:

 

Fe₂O₃

Oxygen = -2 oxidation number

Solve for Fe oxidation number using the number of atoms and known charge of oxygen. Atom charges balance and this equal zero.

 

(? x 2) + (-2 x 3) = 0

(? x 2) - 6 = 0

Fe = +3 oxidation number