Arrange the following sublevels in order of
increasing energy: 3d, 2s, 4s, 3p.

To arrange the sublevels in order of increasing energy, we add the principal shell and the maximum number of electrons of the specific sublevel. s has 2 electrons, p has 6 electrons, d has 10 electrons, and f and 14 electrons. in this case, a) 3 + 10 = 13b) 2 + 2 = 4c) 4 + 2 = 6d) 3 + 6 = 9 
The order hence is 2s, 4s, 3p, and 3d

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.