Question

"if the following set of quantum numbers represents the "last" electron added to complete the ground state electron configuration of an element according to the Aufbau Principle, which one of the following COULD be the symbol for the element?"
n = 3
l = 1
m = 0
s = +,- 1/2
answers:Na,V,Zn,Si,Th

Answer 1

If your n = 3 and your l = 1, the 3 gives the energy level, and the 1 gives the shape. When l = 1 it's a p orbital, so here we're talking about something in the 3p row. The elemetns in the 3 p row include Al, Si, P, S, Cl and Ar. The only element listed in your choices that is in that row is Si.