During light reactions:

carbon dioxide is released by stomata.
hydrogen and oxygen are combined into water.
light energy is converted into chemical energy.
all of the above.

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.