Protons = atomic number
Electrons = atomic number for a neutral atom
Electrons = atomic number – charge for a positive ion
Electrons = atomic number + charge for a negative ion
Neutrons = mass number – atomic number
Mass number = protons + neutrons
Protons = atomic number
Electrons = atomic number for a neutral atom
Electrons = atomic number – charge for a positive ion
Electrons = atomic number + charge for a negative ion
Neutrons = mass number – atomic number
Mass number = protons + neutrons