氧化還原重點（DSE化學）

1. Oxidizing agents gain electrons, in contast, reducing agents lose electrons.

2. The oxidation number of the one which undergoes reduction decreases, and the oxidation number of the one which undergoes oxidation increases.

3. Something that gains oxygen isn't certainly oxidized.

4. Bigger the oxidation number, the substance loses electrons; smaller the oxidation number, the substance gains electrons.

5. The oxidation number of a simple substance is 0.

6. Disproportionation -a chemical reaction in which a single substance acts as both oxidizing and reducing agent, resulting in the production of dissimilar substances. （歧化反應）

7. Elements are conserved, as well as electrons.

8. Sulphite refers to SO3 -, and sulphate refers to SO4 2-.

9. The color of Cr3+ is purple.

10. You can write down the ionic equation of the oxidation and reduction respectively first and then combine them together to work out a complex ionic equation.