Multiple choice

Which of the following is the lightest gas?

  1. Hydrogen

  2. Nitrogen

  3. Ammonia

  4. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrogen is the lightest element in the periodic table, with an atomic mass of approximately 1.008. Because it exists as a diatomic gas (H2), it remains the lightest gas compared to nitrogen or ammonia.