How many protons, electrons, and neutrons does the following isotope contain?
27al 3+

13 protons, 10 electrons, 14 neutrons

Explanation:

First, Al is having a charge of +3, and this means Al has lost 3 of its valence electrons.

Neutral atom of Al has atomic number of 13, but this isn't an atom. This is an ion which has lost 3 electrons, therefore the number of electrons becomes 10 while the number of protons remains 13.

We get the number of neutrons by subtracting the number of protons from the mass number.  In this case, the mass number is 27 and proton number is 13. If you take away 13 from 27, you are left with 14. This is the number of neutrons.

a:

by the combination of an unlimited number of elements