Question

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

Explanation:

Noble - gas notation uses the symbol of the nearest noble gas with a lower atomic number to represent the inner - shell electrons. The element with valence electrons in the 5s sub - shell has electrons starting to fill the fifth energy level. The noble gas just before the start of filling the 5s sub - shell is Kr (krypton), which has a complete electron configuration up to the 4p sub - shell.

Answer:

B. Kr