* Sulfur's Electron Configuration: Sulfur (S) has an atomic number of 16, meaning it has 16 electrons. Its electron configuration is 1s²2s²2p⁶3s²3p⁴.
* Noble Gas Configuration: The nearest noble gas to sulfur is argon (Ar), which has an electron configuration of 1s²2s²2p⁶3s²3p⁶.
* Gaining Electrons: To achieve the same electron configuration as argon, sulfur needs to gain two more electrons. This will fill its 3p subshell.
* Ion Formation: When sulfur gains two electrons, it becomes negatively charged, forming the sulfide ion (S²⁻).
Therefore, the formula of the ion formed when sulfur achieves a noble gas electron configuration is S²⁻.
