Multiple choice

Which is the lightest element in the universe?

  1. Helium

  2. Hydrogen

  3. Nitrogen

  4. Silicon

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

Hydrogen is a chemical element. It is the simplest atom in the Universe. On a periodic table of the elements, hydrogen is on the top row, usually either on the left or on its own above the transition metals.