## Chemistry: The Central Science (13th Edition)

The generalized electron configuration corresponds to the samarium ($Sm$) and plutonium ($Pu$) column. There are 6 unpaired electrons.
[noble gas] $ns^2(n-2)f^{6}$ 1) In this type of question, we would look entirely at the outer-shell electrons (the number of outer-shell electrons, the types of subshells, etc.) - Here we notice that there are only s- and f-subshells involved in the outer shell, so the configurations must be in the lanthanide and actinide series. - There are 2 s-subshell electrons and 6 f-subshell electrons. 6 f-subshell electrons means the 6th column of the lanthanide-actinide series. That corresponds to the samarium ($Sm$) and plutonium ($Pu$) column. 2) The $ns$ subshell is occupied by 2 electrons, so it is completely filled and the electrons are all paired. The $(n-2)f$ subshell is occupied by 6 electrons, while it has 7 orbitals available. According to Hund's rule, these 6 electrons would each occupy a different orbital, which means there are 6 one-electron orbital and 1 zero-electron orbital. Therefore, there are 6 unpaired electrons.