When we go to periodic table, Sulfur is an element that has 16 protons and 16 electrons.
when there is 18 electrons, with number of two electrons more than protons. This makes it an ion and the ion has a -2 charge.
So when there is16 protons, 18 neutrons, and 18 electrons the symbol is S⁻².
The neutrons have no charge but they add only mass to the elements. So when there is 16 neutrons, it doesn't change the symbol of ion.
