# How many electrons are present in the last occupied sublevel of krypton?

Krypton is a noble gas. All noble gases have their valence shells, i.e. their outermost $\text{s}$ and $\text{p}$ sublevels, filled with eight electrons. The representative elements react in order to achieve an octet of electrons in their valence shells, making them stable. Krypton's valence shell has the electron configuration of $\text{4s"^2"4p"^6}$. Since it already has an octet in its valence shell, it is already stable as a single atom.