CH 221 and CH 223 - Oxidation Numbers Tutorial
Questions regarding oxidation numbers? Try this quick tutorial and quiz.
Your answers to these questions will not affect your grade... relax and good luck!
Feel free to contact me if you have any comments or questions regarding this tutorial.
Review of Oxidation Numbers
- Atoms in their Natural State
- Atoms in their natural state will always have an oxidation number of zero.
- Examples include Cl2(g), H2(g), Na(s), Hg(l), N2(g), Fe(s), etc.
- Fluorine
- Fluorine is always -1 in compounds with other elements.
- Oxygen
- Oxygen is always -2 in compounds with other elements except when combined with fluorine or peroxides.
- Chlorine, Bromine and Iodine
- Cl, Br and I will always be -1 in compounds with other elements unless combined with oxygen or fluorine.
- Hydrogen
- Hydrogen is always +1 in compounds with other elements except when combined with metals to form metal hydrides. The oxidation number for a hydride (H-) is -1.
- Ions of a single atom
- For ions with only a single atom, the oxidation number is equal to the charge on the ion.
- For example, the sodium ion, Na+, has an oxidation number of +1.
Test Yourself using Oxidation Numbers
1. What is the oxidation number of P in H3PO4?
2. What is the oxidation number of N in NH4MnO4?
3. What is the oxidation number of Mn in NH4MnO4?
4. What is the oxidation number of C in C2H4O2?
5. What is the oxidation number of Xe in XeO42-?
6. What is the oxidation number of S in H2S?
7. What is the oxidation number of Fe in FeCl5?
8. Does the carbon in CO2 have a higher oxidation number than the carbon in C2H4?
9. Does the sulfur in H2S have a higher oxidation number than the sulfur in S8?
10. Does the sulfur in H2S have a higher oxidation number than the sulfur in H2SO4?
11. What is the oxidation number of H in CaH2?
12. What is the oxidation number of O in OF2-?
13. What is the oxidation number of Cl in OCl-?
14. Does the nitrogen in HNO3 have a higher oxidation number than the nitrogen in NO2?
15. What is the oxidation number of As in H2AsO4-?