Answer
There are four alpha particles and four beta particles (electrons) emitted. The decay path doesn’t matter.
Work Step by Step
The nucleon (mass) number drops by 16, from 222 to 206, which means that four $\alpha$ decays took place.
The atomic number changed by 4, from Z = 86 to Z = 82. The four alpha decays account for a decrease of eight protons, so 4 $\beta^{-}$ decays must have taken place, converting four neutrons into protons.
This decay chain may be traced out in Figure 30–11.
