Answer:
Step-by-step explanation:
Elemental sulfur, or an atom of sulfur has 16 electrons associated with it, and is, therefore, neutral. An S
2−
ion has two electrons more than a neutral S atom, 16+2=18 electrons, and therefore bears a −2 minus charge on it.
The electronic distribution of S is 2,8,6, and that of S
2−
is 2,8,8, which is a stable noble gas distribution.
The two species have an equal number of protons and neutrons, 16 and 16 respectively, but differ only in the number of electrons. S
2−
ion is stable while S atom is not.
Also, the size of S
2−
ion is larger than that of a neutral S atom. This is because in S
2−
ion, the number of electrons is more than the protons, so the nuclear pull on the valence electrons is less. Therefore, the ion expands in size and has a larger radius (size) than the neutral S atom which has an equal number of protons and electrons.