# The radioactive atom ""_84^210 "Po" decays by alpha emission. How would you write an equation showing the decay?

$\text{_84^210"Po"rarr""_82^206"Pb} + \alpha$ or $\text{_84^210"Po"rarr""_82^206"Pb"+""_2^4"He}$
Alpha emission is when a radioactive sample decays by emitting a helium nucleus. The sample thus decays into an atom with whose mass is four $\text{g}$ ${\text{mol}}^{- 1}$ less and whose atomic number is two less.