Which of the following lists includes all the main subatomic particles that make up an atom?

• A. Protons, electrons, and photons
• B. Protons, neutrons, and electrons
• C. Neutrons, electrons, and positrons
• D. Protons, neutrons, and alpha particles

Answer: (B)

Verified step by step guidance

1. Recall that an atom is composed of three main types of subatomic particles: protons, neutrons, and electrons.
2. Understand the role of each particle: protons carry a positive charge and reside in the nucleus, neutrons have no charge and also reside in the nucleus, and electrons carry a negative charge and orbit the nucleus.
3. Identify that photons are particles of light and not constituents of atoms, so they are not included in the list of subatomic particles that make up an atom.
4. Recognize that positrons are the antimatter counterparts of electrons and are not normally part of a stable atom's structure.
5. Note that alpha particles are helium nuclei (2 protons and 2 neutrons) and are not individual subatomic particles within an atom.