When bismuth-212 undergoes alpha decay, it becomes which of the following? a asatine-208 + an alpha particleb lead-210 + an alpha particlec polonium-210 + and alpha particled thallium-208 + and alpha particle

Answer is: D thallium-208 + and alpha particle.
Nuclear reaction: ²¹²Bi → ²⁰⁸Tl + α (alpha particle).
Alpha decay is radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and transforms into an atom with an atomic number that is reduced by two and mass number that is reduced by four.