What Is The Atomic Number Of A Sodium Atom That Has 11 Protons And 12 Neutrons Blank?

What Is The Atomic Number Of A Sodium Atom That Has 11 Protons And 12 Neutrons Blank? 2 Answers. The atomic number, Z , is precisely the number of protons, positively charged, massive, nuclear particles, so Z = 11 . What is the identity of an element with 11 protons 11 electrons and 12 neutrons?