In a balanced nuclear reaction where polonium-212 releases an alpha particle (which consists of 2 protons and 2 neutrons), the atomic number of the daughter isotope (lead in this case) can be calculated as follows:
Polonium has an atomic number of 84. When it emits an alpha particle, it loses 2 protons:
\[ 84 - 2 = 82 \]
So, the atomic number of lead produced in this reaction is 82.
Therefore, the correct option is 82.