In physics, the proton (Greek πρώτον / proton = first) is a subatomic particle with an electric charge of one positive fundamental unit, a diameter of about , and a mass of , or about 1836 times the mass of an electron. History Ernest Rutherford is generally credited with the discovery of the proton. In 1918 Rutherford noticed that when alpha particles were shot into nitrogen gas, his scintillation detectors showed the signatures of hydrogen nuclei. Rut… (More on Proton)