Nitrogen (N_{2}) Neon (Ne) Ozone (O_{3}) Ammonia (NH_{3})
I gave my students this multiple choice question: Which is a compound?

Only one answer is correct among these 4 choices:
- Nitrogen (N_{2})
- Neon (Ne)
- Ozone (O_{3})
- Ammonia (NH_{3})

Could you tell me which one is correct?

Ammonia (NH_{3})