What does the superscript represent in electron configuration notation?

1 Answer
Oct 30, 2016

The superscript represents the number of electrons in that particular orbital sublevel (it does not represent an element inside an orbital).

For example,

1s^color(red)(2) 2s^color(red)(2) 2p^color(red)(5) tells us that there are:

  • 2 electrons in the core 1s orbital of "F"
  • 2 electrons in the core 2s orbital of "F"
  • 5 total electrons combined in the 2p_x, 2p_y, and 2p_z valence orbitals of "F".

" "ul(uarrdarr)" "ul(uarrdarr)" "ul(uarr color(white)(darr))
" "underbrace(" "" "" "" "" "" "" "" ")
" "" "" "" """ 2p

ul(uarrdarr)
"" 2s
" "
" "
" "
" "
" "
" "
" "
" "
ul(uarrdarr)
"" 1s

The total number of electrons tells us that for a neutral element, the atomic number is equal to that number, telling us the identity of the element in question (assuming neutrality).

Thus, I knew it was "F" if I assumed it was neutral and found that obviously, 2 + 2 + 5 = 9, as this is the atomic number of "F".

(Of course, it could have also been "O"^(-), or "Ne"^(+), but those are significantly less realistic.)