What is the automatic number of a sodium atom that has 11 protons and 12 neutrons

The atomic number is precisely the number of protons, positive charged, massive, nuclear particles Z=11. The term we would use for the element for sodium Na. If the sodium atom Z=11 then protons are have the same number of atoms. there must be equal and neutral. If it is a nuclide there must be neutrons in the nucleus.