Respuesta :
Neutron.
Because, the mass of atoms was found to be greater than the mass of protons, scientists believed that there was some other sub atomic particle that added to the mass of protons to give the total mass of atoms.
So the neutron was discovered.
Hope This Helps You!
Because, the mass of atoms was found to be greater than the mass of protons, scientists believed that there was some other sub atomic particle that added to the mass of protons to give the total mass of atoms.
So the neutron was discovered.
Hope This Helps You!