How does the mass of an electron compare to the mass of a proton?

• A. The mass of an electron is exactly half the mass of a proton.
• B. The mass of an electron is much greater than the mass of a proton.
• C. The mass of an electron is much smaller than the mass of a proton.
• D. The mass of an electron is approximately equal to the mass of a proton.

Answer: (C)

Verified step by step guidance

1. Recall the fundamental particles in an atom: electrons and protons are two of the main subatomic particles.
2. Understand that the mass of a proton is approximately 1 atomic mass unit (amu), which is about \$1.67 \times 10^{-27}$ kilograms.
3. Know that the mass of an electron is much smaller, approximately \$9.11 \times 10^{-31}$ kilograms.
4. Compare the two masses by dividing the mass of the electron by the mass of the proton to see the relative difference.
5. Conclude that since the electron's mass is roughly 1/1836 of the proton's mass, the electron is much lighter than the proton.