how many protons are in the nucleus of an aluminum atom?
The atomic number, Z of aluminium, Al is 13. Hence there are 13 protons. Note: Atomic number, Z represents the number of protons in a given atom. Number of neutrons depends on the isotopic form of aluminium. More than 99.9% of naturally occurring aluminium is 13Al27. Where 27 is the mass number, A; and 13 is atomic number, Z.