Multiple choice

Which particles are the smallest in an atom?

  1. protons

  2. neutrons

  3. electrons

  4. Louis

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

Electrons have a negligible mass of about 1/1836 of a proton or neutron, making them by far the smallest and lightest of the three main subatomic particles. Protons and neutrons are much larger and heavier, residing in the nucleus.