Is my analysis of quantum numbers describing the ground state of At correct?

Which series of quantum numbers describes the highest (energy) occupied orbital in a ground state of **At** atom?


a) n = 6, l = 0   

b) n = 6, l = 2   

c) n = 5, l = 2   

d) n = 4, l = 3   

**e) n = 6, l = 1**


According to my teacher, the answer is e.


My analysis: 


* The electron configuration of At atom:


$$\begin{aligned}1s^22s^22p^63s^23p^6\ce{3d^10}4s^24p^64\ce{d^10}5s^25p^64\ce{f^14}\ce{5d^10}6s^26p^5
\end{aligned}$$


Knowing for levels 0,1,2,3 correspond to s,p,d,f respectively we can say that: 


a) $$\begin{aligned}6s^2\end{aligned}$$
b) $$\begin{aligned}Nothing \end{aligned}$$
c) $$\begin{aligned}\ce{5d^10}\end{aligned}$$
d) $$\begin{aligned}\ce{4f^14}\end{aligned}$$
e) $$\begin{aligned}\ce{6p^5}\end{aligned}$$


What I thought here first is that d is the answer since 4f14 has the largest number of electrons, and thus will occupy the highest energy around.


Then I saw on another question that the orbitals are filled so that the ones of lowest energy are filled first.


$$1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s ...$$


In this case, e is the answer since 6p5 has the highest energy regardless of the number of electrons it is holding?




Yes , there is another name for it **(n+l) rule** or *Aufbau principle*


<http://en.wikipedia.org/wiki/Aufbau_principle>


Even though it is not correct to check this rule at such higher values of Z where the trend sometimes changes due to very less differnce between higher values of shell and orbitals .But if you are a beginner you should not heed to this statement.


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