Quantum numbers

[LeAirraBullingor2k]

How would you find the first two quantum numbers of the last electron in an element?

[JasonLiu_2J]

The first two quantum numbers are the n and l quantum numbers. These indicate the energy level and subshell in which the electron resides. For the last electron in the element, you are looking at the valence electron. Thus it would be the farthest orbital, or rather, the first electron that you would take away during ionization. If you wrote out the electron configuration for the atom, it would be the subshell that appears last. For example, the last electron in element Cr would be 4s since the electron configuration is [Ar] 3d5 4s1. This 4s orbital corresponds to the n=4 and l=1 quantum numbers. Hope this helps!