Here's why:
* Atoms are made up of protons, neutrons, and electrons.
* Protons have a positive charge.
* Electrons have a negative charge.
* Neutrons have no charge (they are neutral).
The number of neutrons in an atom can vary, leading to different isotopes of the same element. For example, chlorine has two common isotopes: chlorine-35 and chlorine-37. Both have 17 protons, but chlorine-35 has 18 neutrons and chlorine-37 has 20 neutrons. Despite the difference in neutron count, the charge of the neutron remains the same – neutral.