Goldstein (1886) found that the charge-to-mass (e/m) the ratio of the positive ray particles depends upon the nature of the gas in the discharge tube, i.e., e/m values for the positive rays of different gases are different. The e/m value for positive rays was the highest when hydrogen gas was used in the discharge tube. This is because; hydrogen atom is the lightest atom of all: m is the lowest; hence e/m is the highest.

The particle in the positive rays when hydrogen gas was used in the discharge tube, was given the name proton. A proton is produced when one electron is removed from a hydrogen atom (H).

H H+ + e

Hydrogen proton electron


Thus, the proton is a hydrogen ion (H+).

What are the characteristics of a proton

Proton is a positively charged particle. Its physical characteristics are:

Mass of a proton: the mass of a proton is equal to that of a hydrogen atom. Its mass is about 1840 times that of an electron.


Mass of proton = 1.676 × 10-27 kg= 1.676 × 10-24g