Expert Answers
ncchemist eNotes educator| Certified Educator

Krypton is a group 18 noble gas.  As such, it has a stable octet in its valence shell and is extremetly unreactive.  Its electron configuration is shown below:

1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6

This totals up to 36 electrons, which is the atomic number of krypton.  The 4s2 and 4p6 electrons are the valence shell octet.  The electron configuration can be shorthanded using argon as shown below:

[Ar] 3d10, 4s2, 4p6

atyourservice | Student

`1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 `

and the short hand version would be

`[Ar] 3d^10 4s^2 4p^6`