ANSWER: D
Step 1: Identify the different mass and atomic numbers
- Pu (Plutonium) has mass number 239 and atomic number 94
- Pd (Palladium) has mass number 112 and atomic number 46
- Cd (Cadmium) has mass number 124 and atomic number 48
Step 2: Calculate the mass and atomic number of the missing section
- Mass number is equal to the difference between the mass numbers of the reactants and the products
239 – (112 + 124) = 3
- Atomic number is equal to the difference between the atomic numbers of the reactants and the products
94 – (46 + 48) = 0
- The answer is therefore not B or C
Step 3: Determine the correct notation
- Neutrons have a mass number of 1
- The answer is therefore not A
- Therefore, this must be three neutrons, which corresponds to D