Answer:
Step-by-step explanation:
Hello,
Polonium has the atomic number 83, thus, it has 83 protons and electrons; in such a way, the amount of neutrons is given by the subtraction:
![neutrons=atomic.mass - atomic.number\\neutrons=208-83\\neutrons=125](https://img.qammunity.org/2020/formulas/chemistry/college/7u3f8qfk6afnvnsdvwq925k833e002np33.png)
Now, the addition between the neutrons and electrons is the same atomic mass considering the previous formula, thus:
![electrons+neutrons=83+125=208](https://img.qammunity.org/2020/formulas/chemistry/college/mju3km69esoarb7oiyipyp3zr5tfngil7i.png)
So this procedure could be avoided by just looking at the given information "208Po" which contains the result.
Best regards.