When bismuth-210 undergoes alpha emission, it releases an alpha particle (which is essentially a helium nucleus, consisting of 2 protons and 2 neutrons) and transforms into a different element. The atomic number of bismuth is 83, and when it emits an alpha particle, the atomic number decreases by 2, and the mass number decreases by 4.
The balanced nuclear equation can be written as follows:
Bi-210 → He-4 + Pb-206
Here, bismuth-210 (Bi-210) transforms into lead-206 (Pb-206) after the emission of an alpha particle (He-4). In this equation, the total mass number and atomic number are conserved, which is a fundamental principle of nuclear reactions.