Answer:
Option C is correct = ₈₅At²²⁰
Step-by-step explanation:
Given radioactive decay shows the beta emission.
²²⁰₈₄Po ₈₅At²²⁰ + ⁰₋₁e ⁻
Beta radiations are result from the beta decay in which electron is ejected. The neutron inside of the nucleus converted into the proton an thus emit the electron which is called β particle.
Properties of beta radiations:
1) They can travel in air in few meter distance.
2) These radiations can penetrate into the human skin.
3) The mass of beta particle is smaller than the alpha particles.
4) The sheet of aluminium is used to block the beta radiation
¹⁴₆C → ¹⁴₇N + ⁰₋₁e ⁻
The beta radiations are emitted in this reaction. The one electron is ejected and neutron is converted into proton.