Transcript Oxidation Number - Susquehanna Township School District

Oxidation Number
This is a signed (+ or –) number that
indicates the actual charge or the
apparent charge that an atom of an
element would have in a particular
situation.
Rules for Assigning Oxidation Numbers
Rule #1:
The oxidation number of a free element is zero (0).
Rules for Assigning Oxidation Numbers
Rule #2:
The oxidation number of a monatomic ion is equal
to the charge on the ion.
Rules for Assigning Oxidation Numbers
Rule #3:
The oxidation number of hydrogen when in a
compound is +1; except when combined with a
metal, then it is – 1.
Rules for Assigning Oxidation Numbers
Rule #4:
The oxidation number of oxygen when in a
compound is – 2; except when it would violate
other rules, then it is – 1.
Rules for Assigning Oxidation Numbers
Rule #5:
The oxidation numbers of the atoms of a
compound must add up to zero (0).
Rules for Assigning Oxidation Numbers
Rule #6:
The oxidation numbers of the atoms of a
polyatomic ion must add up to equal the charge on
the ion.
Rules for Assigning Oxidation Numbers
Rule #7:
The oxidation numbers of Group IA elements in a
compound is always +1; Group IIA elements in a
compound always have an oxidation of +2; Group VIIA
elements when written last in a binary compound will
always have an oxidation number of – 1.