(i) Leptons are lighter particles having mass equal to or less than about 207 times the mass of an electron except neutrino and antineutrino.
(ii) This group contains particles such as electron, positron, neutrino and anti neutrino, positive and negative and muons.
(iii) The electron and positron are the antiparticles.
(iv) Neutrino and anti neutrino are also associated with β-ray emission.
(v) The neutrinos and anti neutrinos are massless and chargeless particles, but carrier of energy and spin.