The isotope with 13 protons and 14 neutrons is aluminum-14. The element of the isotope can be determined by either the number of electrons or protons, which are equal to the atomic number of an element. In the case of aluminum, it has an atomic number of 13.
Isotopes are simply atoms that have more or fewer neutrons than it should. This should not be confused with ions, which are atoms that have more or fewer electrons than they should. Isotopes are written as the element followed by a hyphen and the number of neutrons. For the case of aluminum with an extra neutron, it is written as aluminum-14.
