# What is a possible ion that has this electron configuration: 1s^2, 2s^2, 2p^6, 3s^2, 3p^6?

It would be the chloride ion, with a charge of 1^(-)".
A neutral chlorine atom has the electron configuration $\text{1s"^2"2s"^2"2p"^6"3s"^2"3p"^5}$. In an ionic compound, chlorine gains the sixth $\text{3p}$ electron, most likely when reacting with a metal such as sodium (Na), forming the chloride ion, $\text{Cl"^(-)}$.
The image below represents the formation of the ionic compound sodium chloride, $\text{NaCl}$. The bond is formed by the electrostatic attraction between the positive and negative ions.