Simple Examples of Oxidation and Reduction

📚 Quick Study Guide

• ⚛️ Oxidation involves the loss of electrons by a molecule, atom, or ion. Think of it as becoming more positive.
• ⬇️ Reduction involves the gain of electrons by a molecule, atom, or ion. Think of it as becoming more negative.
• 🔄 Oxidation and reduction always occur together in a redox (reduction-oxidation) reaction. You can't have one without the other!
• 🔢 A helpful mnemonic: OIL RIG (Oxidation Is Loss, Reduction Is Gain) of electrons.
• ⚡ Oxidizing agents cause oxidation by accepting electrons, and they themselves are reduced.
• 🔋 Reducing agents cause reduction by donating electrons, and they themselves are oxidized.
• ⚖️ The oxidation state (or oxidation number) is a measure of the degree of oxidation of an atom in a chemical compound. It's the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic.

🧪 Practice Quiz

1. Which of the following describes oxidation?
1. A. Gain of electrons
2. B. Loss of electrons
3. C. No change in electrons
4. D. Gain of protons


2. In the reaction $Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$, which species is oxidized?
1. A. $Cu^{2+}$
2. B. $Zn$
3. C. $Cu$
4. D. None of the above


3. Which of the following is a reducing agent?
1. A. A substance that gains electrons
2. B. A substance that loses electrons
3. C. A substance that causes oxidation
4. D. All of the above


4. What happens to the oxidation number of a substance when it is reduced?
1. A. Increases
2. B. Decreases
3. C. Stays the same
4. D. Becomes zero


5. In the reaction $2Na + Cl_2 \rightarrow 2NaCl$, which species is reduced?
1. A. $Na$
2. B. $Cl_2$
3. C. $NaCl$
4. D. None of the above


6. Which statement is true about oxidizing agents?
1. A. They cause reduction and are oxidized.
2. B. They cause oxidation and are oxidized.
3. C. They cause reduction and are reduced.
4. D. They cause oxidation and are reduced.


7. What is the oxidation number of oxygen in $H_2O$?
1. A. +2
2. B. -2
3. C. +1
4. D. -1