Calculate Oxidation Numbers Video Lessons

Concept:

# Problem: Determine the oxidation number for the indicated element in each of the following compounds:(a) N in GaN(b) Cl in HClO2(c) Cr in BaCrO4

###### FREE Expert Solution

The rules for oxidation states are as follows:

A. General Rules:

1. For an atom in its elemental form (Zn, Cl2, C(graphite), etc.)    O.S. = 0

2. For an ion (Li+, Al3+, etc.)                                                       O.S. = charge

B. Specific Rules:

1. Group 1A              O.S. = +1

2. Group 2A              O.S. = +2

3. Hydrogen              O.S. = +1, with nonmetals

O.S. = –1 with metals and boron

4. Fluorine                 O.S. = –1

5. Oxygen                  O.S. = –1 in peroxides (X2O2, X = Group 1A)

O.S. = –1/2 in superoxides (XO2, X = Group 1A)

O.S. = –2 in other compounds

6. Group 7A               O.S. = –1 (except when bonded to O)

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###### Problem Details

Determine the oxidation number for the indicated element in each of the following compounds:

(a) N in GaN
(b) Cl in HClO2
(c) Cr in BaCrO4