Here's why:

* Neutrons are subatomic particles found in the nucleus of atoms, alongside protons.

* Protons have a positive charge, while neutrons have no charge (they are neutral).

* The number of neutrons in an atom determines its isotope. Different isotopes of the same element have the same number of protons but a different number of neutrons.

* The mass of a neutron is slightly greater than the mass of a proton.