Question

Radon-222 is an alpha emitter with a half life of 3.82 days.

Answer 1

The daughter isotope (a decay product): Polonium (Po)

Further explanation

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

• alpha α particles ₂He⁴

• beta β ₋₁e⁰ particles
• gamma particles γ
• positron particles ₁e⁰

Radon-222 emits alpha α particles ₂He⁴  , so the atomic number decreases by 2, mass number decreases by 4

Reaction

$\tt _{86}^{222}Rn\Rightarrow _{84}^{218}+_2^4He$

1. The mass number of the daughter isotope = 218

2 and 3. If we look at the periodic system, the element with atomic number 84 is Polonium (Po)