Calculate Oxidation Numbers Video Lessons

Concept: Oxidation Number

Problem: Determine the oxidation number (oxidation state) of each element in the following six compounds.(a) CuCO3 (b) CH4(c) IF(d) CH2Cl2(e) SO2(f) (NH4)2CrO4

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 (oxidation state) of each element in the following six compounds.

(a) CuCO3

(b) CH4

(c) IF

(d) CH2Cl2

(e) SO2

(f) (NH4)2CrO4