May 04, 2020
The electric charge of an electron is an intrisic quantity of sub-atomic particles. It is negative and measured in Coulomb (about -1.6 10^-19 C which we'll write -e) whereas the one of a proton is positive (+e) and the one of a neutron is null. Two electric charges of the same sign (for example, two electrons) repel each other while two electric charges of the opposite sign attract each other. The amplitude of this attracting / repulsing force is:
F = k q_1 * q_2 / (r * r)
(where F is the electrique force, also called electrostatic force, k is a constant (the Coulomb's constant), q_1 and q_2 are the electric charge of the particles and r is the distance separating the charges).
In conductive materials, such as most metals, electrons can freely move and hop from one atom to the other where there is some space available while atomic nucleus are fixed. Using the electric attraction/repulsion forces, we can force electrons to move through a conductive material. This creates a current (= moving eletric charges).