Step-by-step explanation:
The following are the second ionization energies for the elements:
Mg = 15.03 eV
Si = 16.34 eV
P = 19.76 eV
Al = 18.82 eV
Na = 47.28 eV
From the above, it is clear to observe that Na has the largest second ionization energy.
Answer:
Na is the answer.