Chemistry › Isotope
Mendeleev · Isotope
Sodium-23
Sodium-23: atomic number 11, mass number 23, with 11 protons and 12 neutrons.
IsotopeNa
2311Na
Protons11
Neutrons12
Electrons (neutral)11
The proton count fixes the element: 11 protons identify Sodium. Mass number 23 is the total number of protons and neutrons.
A neutral Sodium-23 atom also has 11 electrons. Changing neutrons changes the isotope; changing electrons changes the charge.