An unexpected change in is a sign that a chemical reaction may have occured.

Substances giving off a smell or
while being combined is also an indicator of a chemical

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.