Which particle in an atom is uncharged and located in the nucleus?

In an atom, the particle that is uncharged and located in the nucleus is the neutron. Neutrons play a crucial role in the stability of the nucleus, where they help to offset the repulsive forces between the positively charged protons. Since neutrons have no charge, they do not contribute to the electrical interactions in the same way protons do, which are positively charged, and electrons, which are negatively charged. The presence of neutrons in the nucleus allows for a balanced structure, especially in larger atoms where additional protons would generate significant repulsion if not for the stabilizing effect of neutrons. Photons, while they are involved in electromagnetic interactions, are not particles that make up the nucleus; rather, they are particles of light. Thus, the neutron is the correct choice in this context, as it is specifically defined by its lack of charge and its positioning within the atomic nucleus.