Answer:
102/46Pd
Step-by-step explanation:
The mass numbers and the atomic numbers must balance on both sides of the equation. The product side shows a beta particle, indicating that this is a beta decay equation.
Beta decay doesn’t change the mass number of the original atom, so the mass number of the atom on the product side will be the same as the mass number of the atom on the reactant side, 102.
The sum of the atomic numbers on the product side needs to be 45, which is the atomic number of the reactant side. So, the atom on the product side must have a mass number of 46.
Use the periodic table to find the element to be palladium (102/46Pd).