Electron is a negatively charged particles having very small mass. Mass and charge of an electron are given below.

(i) Mass of an electron (me): The mass of a electron is about 1/1840 times that of a hydrogen atom. Its absolute mass is ,

me= 9.108 × 10-31kg=9.108 × 10-28g

It is a very light particle, and therefore, it makes very little contribution to the total mass of the atom in which it is contained.

(ii) Charge on an electron (e): an electron possess one unit negative charge, it has been found to be the smallest negative charge that any particle can carry.

Charge on an electron, e = – 1.602× 10-19 Coulombs.