# 2. How many protons, neutrons, electrons are in an ion of sulfur (S^-2)?

Oct 8, 2016

For ""^32S^(2-), there are 16 protons, 18 electrons, and 16 neutrons.

#### Explanation:

The atomic number, $Z$, specifies the number of protons, positively charged, massive, fundamental particles present in the sulfur nucleus. This number defines the sulfur atom as a sulfur atom (i.e if there were 17 protons, the atom would be chlorine).

For a neutral atom, if there are 16 positive nuclear charges, there must necessarily be 16 negatively charged particles, 16 electrons, whizzing about the nucleus.

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 ""^32S^(2-) ion, there are 18 electrons, 16 protons, and 16 neutrons.