What are found in the nucleus of an atom?

• A. Protons and Neutrons
• B. Electrons
• C. Photons
• D. Quarks

Answer: (A)

At the heart of the atom is the nucleus, which houses the protons and neutrons—the particles collectively called nucleons. Protons carry a positive charge, neutrons have no charge, and together they contribute nearly all of the atom’s mass. The electrons orbit this core in regions called electron shells, held in place by the electrostatic attraction to the positively charged nucleus. Photons are particles of light and are not constituents of the nucleus. Quarks are the fundamental pieces that make up protons and neutrons, but they reside inside those nucleons rather than existing as separate components of the nucleus. So what is found in the nucleus are protons and neutrons.