Aluminum-27 has a mass, of course, of 27. (Mass is how many protons and neutrons in an atom). Aluminum-27 is an isotope, therefore only the amount of neutrons change and since the are 13 protons, there will be 14 neutrons. Now let's compare:
Silicon-27 would have 13 neutrons
Sulfur-30 would have 14 neutrons
The answer is B.Sulfur-30
