The net charge on a sulfide ion, "S"^(2-), is 2-. How does this ion obtain its charge?

1 Answer
Nov 6, 2016

A neutral sulfur atom gains $2$ electrons.

Explanation:

An ion can only be formed when a neutral atom gains or loses electrons.

Since electrons carry a negative charge, gaining electrons will result in the formation of a negatively charged ion, or anion. Similarly, losing electrons will result in the formation of a positively charged ion, or cation.

In your case, the sulfide anion, ${\text{S}}^{2 -}$, carries a $\left(2 -\right)$ negative charge, which can only mean that it gained electrons.

More specifically, it gained $2$ electrons. A neutral sulfur atom has an atomic number equal to $16$, which means that it has $16$ protons inside its nucleus and $16$ electrons surrounding its nucleus.

For each electron gained, the ion's overall charge decreases by $1$ unit, which further confirms the fact that the neutral sulfur atom gained $2$ electrons to get the $\left(2 -\right)$ charge.