Student Inquiry

[Jason Rutland]

To those who may wish to respond,

My name is Jason and I am a student in Toronto, Ontario. I would like to
know what experiment (specifics please!) did Ernest Rutherford perform
in order to mass the nucleus of the Atom in order to conclude that the
protons in the nucleus did not account for the full mass of the atom
thus leading him to the realization that another subatomic particle
(neutrons) existed?

Sincerely,

Jason Rutland