Which of the following statements does NOT describe the structure of an atom?

• A. The nucleus contains most of the atom's mass.
• B. Atoms are composed only of protons and electrons.
• C. Protons and neutrons are found in the nucleus of the atom.
• D. Electrons are located in energy levels surrounding the nucleus.

Answer: (B)

Verified step by step guidance

1. Review the basic structure of an atom: it consists of a nucleus containing protons and neutrons, and electrons that occupy energy levels (or orbitals) around the nucleus.
2. Understand that the nucleus contains most of the atom's mass because protons and neutrons are much heavier than electrons.
3. Recall that electrons are negatively charged particles found in energy levels surrounding the nucleus, not inside the nucleus.
4. Identify that the statement 'Atoms are composed only of protons and electrons' is incorrect because it excludes neutrons, which are also fundamental components of the atom's nucleus.
5. Conclude that the incorrect statement is the one that says atoms are composed only of protons and electrons, as it does not accurately describe the atomic structure.