Question

Why is an electron negative?

Answer 1

Hint: The electrons were discovered from the cathode rays because there were particles in the cathode rays that were deflected towards the positive plate of the electric field. These are the particles that neutralize the positive charge of the protons present in the nucleus of the atom.

Complete step-by-step answer:The electrons were discovered from the cathode rays because there were particles in the cathode rays that were deflected towards the positive plate of the electric field. And we know that the negative particles are attracted towards the positive one and the positive particles are attracted towards the negative one. So, the electrons were deflected towards the positive plate because there is a negative charge on the electrons. This negative charge on the electron makes it a negative particle.
These are the particles that neutralize the positive charge of the protons present in the nucleus of the atom because in an atom there are equal numbers of electrons and protons, and the protons one unit positive charge and electrons have one unit negative charge.
The charge on the electron is equal to:
$1.60\text{ x 1}{{\text{0}}^{-19}}C$
And the mass of the electron is:
$9.11\text{ x 1}{{\text{0}}^{-28}}$ grams
So, Millikan discovered the charge to the mass ratio of the electron is:
$1.76\text{ x 1}{{\text{0}}^{8}}$ coulombs /grams
But the relative charge of the electron is taken as 1 unit negative charge and the relative mass is taken as 1/1837^th mass of the hydrogen atom.

Note: Besides electrons, protons and neutrons are also fundamental particles, protons were positive because they had one unit positive charge while the neutron is neutral because it doesn’t have any charge.