Nitrogen atoms are different sizes. Nitrogen atoms are different ages. Nitrogen atoms can bond to different atoms. Nitrogen atoms have different amounts of energy.
I gave my students this multiple choice question: The element nitrogen can be found in simple, nonliving substances, such as air, and in complex molecules in living organisms, such as DNA. Which statement explains why nitrogen can exist in many compounds?

Only one answer is correct among these 4 choices:
- Nitrogen atoms are different sizes.
- Nitrogen atoms are different ages.
- Nitrogen atoms can bond to different atoms.
- Nitrogen atoms have different amounts of energy.

Could you tell me which one is correct?

Nitrogen atoms can bond to different atoms.