Figure 14-1 shows the decay of a neptunium-238 over a period of 10 days. what is the half life of neptunium-238? 

It is probably 116I forgot how to do this but it is 1/2

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.