How would one find the first order taylor series expansion of f (x, y) = x sin (y)
about a point (a, b)

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.

No. an alpha particle is a pair of protons and a pair of neutrons, i.e. a helium