Core
Reactions: Redox
Slide 13 of 42
Oxidation state
assignments rules
3.
The oxidation states of elements in a compound is zero.
Compound Oxidation state of
atoms
Eg. NaCl oxidation
# of Na + that of Cl = 0
Na2O 2 (oxidation # of Na) + that of O
= 0
H2SO3 2 (oxidation # of H) + that of S
+ 3 (that of O) = 0
4. The sum of oxidation states in a complex or polyatomic ion equals
the charge on the ion.
Oxidation state of
atoms
Eg. SO4–2 oxidation # of S + 4 (that of O) = –2
MnO4– oxidation # of Mn + 4(that of O) = –1
[CoCl4] –2 oxidation # of Co + 4(that of Cl)
= –2