The atomic number of an element represents the number of protons in its nucleus. In this case, since the atomic number is 13, the element is aluminum (Al).
The mass number of an element represents the total number of protons and neutrons in its nucleus. In this case, the mass number is 27.
To find the number of neutrons, subtract the atomic number from the mass number:
Number of neutrons = Mass number - Atomic number = 27 - 13 = 14
Therefore, aluminum (Al) with an atomic number of 13 and a mass number of 27 has 14 neutrons.