The mass of aluminum with a total nuclear charge of 1.3 c and an atomic number of 13 is 27 atomic mass units (amu).
The student is asking for the mass of aluminum that has a total nuclear charge of 1.3 c and has an atomic number of 13. Since aluminum has an atomic number of 13, it means it has 13 protons and 13 electrons.
To find the mass of aluminum, we need to subtract the number of neutrons from the mass number. Since the aluminum is an isotope with 14 neutrons, the mass number would be 27 (13 protons + 14 neutrons). Therefore, the mass of aluminum is 27 atomic mass units (amu).