When particles are added volume will

Volume will increase. As you put particles back together then it would make it a lot heavier, giving it more volume. 

The volume will increase it means more mass is being added to the object or liquid :)

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.