Step-by-step explanation:
20984Po→20582Pb+42α
4520Ca→4521Sc+0-1e+00ν
Step-by-step explanation:
The alpha decay of polonum-209, which consists of the emission of an alpha particle, will leave behind the atom of a different element.
Notice that the identity of the element changes after the decay. This means that you're dealing with a nuclear transmutation, a process that converts an atom of a given element into an atom of a different element.