* Sulfur's Atomic Number: Sulfur (S) has an atomic number of 16, meaning it has 16 protons.
* Neutral Sulfur: A neutral sulfur atom also has 16 electrons to balance the 16 protons.
* Calculating the Charge: With 18 electrons, sulfur has gained 2 extra electrons (18 - 16 = 2).
* Ion Notation: Since it gained electrons, sulfur becomes a negatively charged ion. The ion notation is S²⁻.
Therefore, the ion notation for sulfur with 18 electrons is S²⁻.
