Configurations for Gchem

[Sammy1024]

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So I was doing this question:

50. Which of the following electronic configurations is the ground state electronic configuration for aluminum?

I know it has 13 electrons which would be [Ne] 3s23p1 but I thought that it would be more stable if it took the 2 electrons from s and made it a half filled p orbital. ([Ne]3p3

Is this wrong? Or am I answering a different question? I know this tends to happen for d-orbitals because i've seen it a lot.

 

[Teleologist]

You take the electrons from the highest energy level first. So in terms of energy level, if n is the same, then s < p < d < f. We take electrons from the s-orbitals first for the d-block elements because think about their configurations: they're all [Noble gas]4s^2 3d^something. The fourth energy level is greater in energy/further from the nucleus than the third energy level. That's why we take away those 4s electrons. So don't think about it in terms of spdf only; also consider distance from nucleus.

 

[Sammy1024]

Oh I see. Since p is greater than s you can't take the electrons but s is higher than d usually so you can take the electrons. Thanks! :]