What is the electron configuration of #"Na"^(+)#? How many paired electrons does it have?
Well, the typical ion that sodium (Na) forms, as an alkali metal (first column in the periodic table) is a
As a neutral atom, its electron configuration was:
Or in longer-hand notation:
#color(blue)ul(1s^2 2s^2 2p^6)#
All "noble gas cores" have all electrons paired. We say that
Therefore, all the electrons in
(I'll leave it as an exercise for you to count how many electrons are paired from the electron configuration given by
I hope that helps!