Which symbols would be included in the noble gas notation for an element that had valence electrons in the 5s subshell?
ar
kr
xe
rn

Kr.

Explanation:

1) The noble gas notation is used to abbreviate the writing of the electron distribution.

This is normally done because for many chemical explanations and predictions it is only important to deal with the valence electrons.

And that is what the noble gas notation shows. The noble gas notation indicates the symbol ot the noble gas immediately previous to the elment considered, inside square brackets, and after that shows the orbitals occupied by the rest of trhe electrons.

2) For example the element lithium has 3 electrons, so its regular (expanded) electron configuration is 1s² 2s. Since, the noble gas previous to lithium is helium, the noble gas notation is [He] 2s.

Other example. Aluminum has `3 electrons. Its regular electron distribuition is: 1s² 2s² 2p⁶ 3s² 3p, and, since the previous noble gas is neon, the noble gas configuration is [Ne] 3s² 3p.

3) Dealing with the question, you have that the noble gas previous to an element that had valence electrons in the 5s subshell is the noble gas in the period (row) number 4, which is Kr.

So, the noble gas of such element would be either [Kr] 5s or [Kr] 5s², depending on whether it has one or two valence electrons in the subshell s (assuming no electrons in the the orbitals 5p).