All of the following can be used to define a base except
a hydronium ion donor in a reaction
a substance that increases the concentration of hydroxide ions
an electron pair donor in a reaction
a substance that is a hydrogen ion acceptor in a reaction

A base is not defined as a substance that donates hydronium ions, it donates hydroxide ions. The first option is correct.

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.