Which particles are characterized by having physical mass but no electrical charge?

Neutrons are the particles that have physical mass but no electrical charge. They are one of the three primary components of an atom, along with protons and electrons. Protons carry a positive electrical charge, and electrons carry a negative charge, while neutrons are neutral, meaning they do not have any electrical charge associated with them. This neutrality is significant because it allows neutrons to contribute to an atom's overall mass without affecting its electrical properties. In the nucleus of an atom, neutrons help to stabilize the protons, which are repelled from each other due to their positive charges. Understanding the role of neutrons is crucial in fields like nuclear physics and chemistry, where the balance of particles influences the stability and reactions of atomic structures. Additionally, positrons, being the antiparticles of electrons, also carry a positive charge, which further differentiates them from neutrons.