Multiple Choice
What is the oxidation number of carbon in CO?
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6. Chemical Quantities & Aqueous Reactions
Calculate Oxidation Numbers
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
What is the oxidation number of oxygen in most compounds?
A
+2
B
-1
C
0
D
-2
Verified step by step guidance1
Recall that the oxidation number (or oxidation state) is a hypothetical charge assigned to an atom in a compound, assuming that electrons in all chemical bonds belong entirely to the more electronegative atom.
Understand that oxygen is highly electronegative and typically gains electrons when forming compounds, which affects its oxidation number.
Remember the common oxidation states of oxygen: in most compounds, oxygen has an oxidation number of -2 because it usually gains two electrons when bonding.
Note exceptions where oxygen has different oxidation numbers, such as -1 in peroxides (e.g., H2O2), 0 in elemental oxygen (O2), and positive values in compounds with fluorine, but these are less common.
Therefore, for most compounds, assign oxygen an oxidation number of -2.
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