Where is most of the mass of an atom located?

• A. In the electron cloud
• B. In the nucleus
• C. In the outermost shell
• D. Evenly distributed throughout the atom

Answer: (B)

Verified step by step guidance

1. Recall the basic structure of an atom, which consists of a nucleus at the center and electrons surrounding it in the electron cloud.
2. Understand that the nucleus contains protons and neutrons, which are much more massive than electrons.
3. Recognize that electrons have very little mass compared to protons and neutrons, even though they occupy most of the volume of the atom.
4. Conclude that since protons and neutrons are concentrated in the nucleus and have most of the mass, the majority of an atom's mass is located in the nucleus.
5. Therefore, the correct answer is that most of the mass of an atom is located in the nucleus.