Which element has this electron configuration?
astatine
bromine
chlorine
fluorine

Unfortunately you did not specify the electronic configuration in the question, however since one of the answers must be a halogen, i took the liberty to attach an image with the configuration (both the simple numeric and spdf form) for all the halogen and all you have to do is match the electronic configuration you have in your question to the one in the table attached and you can then deduce the answer.

Hope this helps.

Ametal with a large number of free flowing electrons most likely has good conductivity