CAS CH 101 Study Guide - Quiz Guide: Cadmium Sulfide, Lithium Oxide, Valence Electron

what is the number of valence electrons, core electrons, andunpaired electrons in the ground state of carbon?

For each element, indicate the number of valence electrons, core electrons, and unpaired electrons in the ground state: (a) nitrogen, (b) silicon, (c) chlorine.

The electron configuration of Mn (element 25) and the number of unpaired electrons are

(a) [Ar] 4s² 3d⁵, 5 unpaired electrons

(b) [Ar] 4s² 4p⁵, 1 unpaired electron

(c) [Ar] 3d⁷, 3 unpaired electrons

(d) [Ar] 4s² 3d⁵, 1 unpaired electron

(e) [Ar] 4s¹ 3d⁶, 5 unpaired electrons

The answer is A, but how to get the number of unpaired electrons, can anybody show me how?