How would you write a full set of quantum numbers for the outermost electron in an Rb atom?
Start by writing the complete electron configuration fir a neutral rubidium atom.
#"Rb: " 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 color(red)(5)s^1#
So, the outermost electron in a rubidium atom is located on the fifth energy level, in an s-orbital.
As you know, four quantum numbers are used to describe the position and spin of an electron inside an atom.
The principal quantum number,
The angular momentum quantum number,
and so on. Since your electron is located in the s-subshell, you will have
The magnetic quantum number,
Finally, the spin quantum number,
#m_s = +1/2 ->#spin-up electron
#m_s = -1/2 ->#spin-down electron
For you electron, you can select
#n=5, l=0, m_l =0, m_s = +1/2#
The electron is located on the fifth energy level, in the 5s-subshell, in the 5s-orbital, and has spin-up.