Answer:
Proton = 13
Electron = 10
Neutron = 14
Step-by-step explanation:
Al3+ means Al that has lost 3 electrons. Al has 13 protrons and 13 electrons. Having lost 3 electrons, Al3+ is left with 10 electrons.
Neutron + protron = relative atomic number
n + 13 = 27
n = 27 - 13 = 14