Chemistry › Isotope
Mendeleev · Isotope
Nitrogen-15
Nitrogen-15: atomic number 7, mass number 15, with 7 protons and 8 neutrons.
IsotopeN
157N
Protons7
Neutrons8
Electrons (neutral)7
The proton count fixes the element: 7 protons identify Nitrogen. Mass number 15 is the total number of protons and neutrons.
A neutral Nitrogen-15 atom also has 7 electrons. Changing neutrons changes the isotope; changing electrons changes the charge.