An electron is a negatively charged elementary particle that constitutes an atom, denoted as e- or β-. The electrons are present in the outer-nuclear region of an atom as clouds.
An electron is 1836 times lighter than its nuclear components- the proton or the neutron, having a mass of only 9.109382 X 10-31 kg. Its contribution to the atom's mass is insignificant (0.06%); however, the electrons occupy almost all the atom's volume.
The electrons move continuously in an atom to counteract the attractive nuclear pull due to the positively charged protons.
To maintain an atom's electrical neutrality, the number of protons always equals the number of electrons. Atoms undergo chemical reactions when the number of electrons is lesser or more than the proton number; therefore, the electrons are solely responsible for bonding and other chemical reactions.