Respuesta :
Answer:
84
Explanation:
- The nuclear equation shows the decay of Radon-222 by emitting an alpha particle to form polonium-218.
- When a radioactive isotope undergoes alpha-decay, the mass number is decreased by 4 while the atomic number decreases by 2.
- Therefore, the complete nuclear equation is;
²²²₈₆Rn → ²¹⁸₈₄Po + ⁴₂He
- The atomic number of Radon-222 decreases from 86 to 84 while the mass number decreases from 222 to 218, forming polonium-218.