The law of charge conservation states that electric charge can neither be created nor be destroyed.
The SI unit of electric charge is the coulomb, symbol C. The magnitude of the charge on a single electron is a commonly used quantity in atomic physics. It is
e ≡ 1.6 x 10-19 C
1C ≡ 6.2 x 1018 e
Thus, the charge on an electron is -e, and on a proton,+e.