Sulfur can form ions with a “-2” charge. Is it a cation or an anion?
The Correct Answer and Explanation is:
Sulfur, when it forms ions with a “-2” charge, is an anion.
Explanation:
An atom can become an ion by either losing or gaining electrons. The charge on the ion depends on the number of electrons it gains or loses relative to its neutral state. In the case of sulfur, it is a non-metal located in group 16 of the periodic table. The elements in this group, such as oxygen, sulfur, selenium, and others, have six valence electrons.
Sulfur has the electron configuration of [Ne] 3s² 3p⁴ in its neutral state, which means it has six electrons in its outermost shell. To achieve a stable electron configuration, similar to the noble gases (which have full outer electron shells), sulfur tends to gain two electrons. By gaining these two electrons, sulfur achieves a complete octet, similar to the noble gas argon, which has a stable, full outer electron shell of eight electrons.
When sulfur gains two electrons, it acquires a negative charge because electrons are negatively charged, and now there are more electrons than protons in the atom. This results in a sulfide ion (S²⁻), which has a “-2” charge. Because the ion has a negative charge (due to the addition of electrons), sulfur is classified as an anion.
Anions are ions that have gained electrons and therefore carry a negative charge. On the other hand, cations are ions that lose electrons and carry a positive charge. Since sulfur gains electrons to form an S²⁻ ion, it is specifically an anion and not a cation.
In summary, when sulfur forms an ion with a “-2” charge, it becomes a sulfide anion (S²⁻), which is classified as an anion due to the negative charge resulting from the gain of two electrons.