How does the charge of one electron compare to that of another electron? how does it compare with the charge of a proton? how do the masses of protons and electrons compare?

a) The charge of one electron is the same charge of another electron.

b) The charge of one electron  has the same magnitude and opposite sign as the charge of a proton. The charge of an electron is negative by convention and the charge of a proton is positive by convention.

c) The mass of a proton is about 1,836 times the mass of an electron.

Explanation:

1) Electron discovery is due to J.J Thompson who is responsible for the famous experiment of the cathode-rays tube.  J.J Thompson, in 1897, found that cathode rays could be deflected by an electric field. He could establish that electrons had negative charge, and also determined the approximate the ratio of its charge to the mass. Yet, he could not determine such magnitudes.

2) Later on, Ernest Rutherford,  with the famous gold foil experiment, found that all of the positive charge (proton) and essentially all of the mass of the atom is concentrated in a tiny region which he named the nucleus.

3) Since, the atom has the same number of electrons and protons, and it is neutral, the charge magnitude of the charges electrons and protons are equal.

4) Robert Millikan, 1908 - 1917, was able to determine the charge of the electron, with which the mass was also determined.

The accepted relative values for the subatomic particles are:

Particle   Relative massRelative charge

Proton           1                              +1

Neutron        1                                0

Electron        1/ 1,836                    -1