Which of the following is a characteristic property of the halogens?A.They are metals.B.They are very stable.C.They are very reactive.D.They are all gases.

Step 1: Analyze the Options

To determine the characteristic property of halogens, let's analyze each option:

1. A. They are metals.
   This is incorrect; halogens are nonmetals.

2. B. They are very stable.
   Halogens are not generally considered stable as they readily react with other elements.

3. C. They are very reactive.
   This is true; halogens are known for their high reactivity, especially with alkali metals and alkaline earth metals.

4. D. They are all gases.
   This option is incorrect because, while fluorine and chlorine are gases at room temperature, bromine is a liquid, and iodine is a solid.

Step 2: Conclusion

Based on the analysis, the characteristic property that accurately describes the halogens is:

Final Answer

C. They are very reactive.