What percentage of an atom's mass is in its nucleus?
A) Over 99.9%
B) Over 99% but less than 99.9%
C) Over 90% but less than 99%
D) Less than 90%

Question

Quizplus · Accepted Answer

The nucleus of an atom contains protons and neutrons, which account for more than 99.9% of the atom's total mass. The electrons, which orbit the nucleus, have much less mass and contribute minimally to the total mass of the atom.

What Percentage of an Atom's Mass Is in Its Nucleus