A electron is one of the three main components of the atom. The other two are the proton and the neutron .
Electrons exist outside of the nucleus of an atom, essentially in orbit around it.
The electron is the fundamental unit of negative charge, carrying a charge of -1. Electrons are held in the atom by electrostatic attraction to the positively charged protons in the nucleus. Under some circumstances, however, electrons can escape from the atom. The flow of electrons in one direction creates an electric current. In an uncharged atom, the number of protons is equal to the number of electrons.