which of the following symbols would be included in the noble gas notation for an element that had valence…

which of the following symbols would be included in the noble gas notation for an element that had valence electrons in the 5s subshell?\nar\nkr\nxe\nrn
Answer
Brief Explanations:
Noble - gas notation uses the symbol of the last noble gas before the element in question. The 5s sub - shell comes after the noble gas Kr (krypton). The noble gas that precedes elements with valence electrons in the 5s sub - shell is Kr.
Answer:
B. Kr