Which subatomic particle has no charge?

The neutron is a subatomic particle with no electric charge, which is why it is the correct answer. Neutrons are found in the nucleus of an atom alongside protons, which are positively charged. The absence of a charge in neutrons plays a crucial role in the stability of the atomic nucleus. While the forces between protons, which repel each other due to their like charges, could cause the nucleus to break apart, neutrons help to mediate those forces and provide stability to the nucleus by acting as a buffer.

In contrast, protons carry a positive charge and electrons have a negative charge, both of which are fundamental to the behavior of atoms in chemical reactions and interactions. The term "hydron" does not refer to a specific subatomic particle but rather a generic term for any ion of hydrogen, which typically refers to a proton or hydrogen ion. Therefore, the neutron’s lack of charge is key to its role in the atomic structure and in the context of this question.