Q. Which of the following are common features of noble gases?

1. They are monoatomic under standard conditions.
2. They have very high ionization enthalpy.
3. They show extremely low chemical reactivity.
4. They readily form stable diatomic molecules under normal conditions.

Select the correct option using the codes given below:
Answer: 1, 2 and 3 only
Notes: Noble gases (He, Ne, Ar, Kr, Xe, Rn) are monoatomic under standard conditions, possess very high ionization enthalpy due to stable electronic configurations, and exhibit very low chemical reactivity. They do not readily form stable diatomic molecules under normal conditions. Thus, statements 1, 2, and 3 are correct, while 4 is incorrect.