It is a beta particle that is being emitted when the radioactive nucleus of 131 / 53 I decays to form the stable isotope of xenon 131 / 54 Xe. It is written as 0/-1 e-. It is a high speed and high energy positron or electron during beta decay. An unstable nucleus containing an excess of neutrons would unergo a beta decay wherein the neutron is transformed into a proton, and electron and an antiparticle. The electrons emitted are not the electrons from the shells but are being produced when a neutron splits firming a proton and an electron. These particles would be able to pass in paper but can be blocked by an aluminum foil.
Barium chloride and lithium sulfate are mixed, barium sulfate and lithium chloride are formed. Barium sulfate is obtained as a white precipitate and lithium chloride as an aqueous solution.
