Spin quantum number for the last electron in potassium is?

1 Answer
Jun 11, 2018

#+1/2#

Explanation:

Electronic configuration of Potassium (#""_19"K"#) is

#"1s"^2\ "2s"^2\ "2p"^6\ "3s"^2\ "3p"^6\ "4s"^1#

Last electron is in #"4s"# sub-shell. As a convention spin quantum number of first entering electron in an orbital is assigned as #+1/2#