Core
Reactions: Redox
Slide 10 of 42
Charge and
Oxidation state
Oxidation state however can be assigned to all atoms (elements)
in every kind of chemical environment, whether it is part of an
ionic compound, polyatomic ion or a molecule.
In the case of binary ionic compounds, oxidation state of the
elements in the compound is the same as the charge on the
ions.
–So,
oxidation state of a monatomic charged ion is the same as the charge on
it.
What about oxidation state of an element in a covalent compound
or an element that is part of a polyatomic ion?
–With
both covalent substances and polyatomic ions,
•positive
oxidation state is assigned to the element that appears first in the formula
(with some exceptions, notably some binary compounds and polyatomic
ions of hydrogen such as NH3, CH4, NH4+ etc.), and
•negative
oxidation state to the one that appears to the right (the more electronegative
one–the one with stronger attraction for the shared electrons).