What is the greatest number of electrons with n=3 that could exist in an atom?

[iliveinmyguitar]

Hey guys,

This question is bothering me because I have found explanations that say that when n= 3 we can have 0,1,2, or s,p,d.

s orbital can have a max of 2
p orbital can have a max of 6
d orbital can have a max of 10

total= 18, which is the right answer but I don't understand why it can't be 30 since if you look at the periodic table you can see that Zinc is the biggest atom with n=3 and it has a total of 30 electrons in its ground state. I just can't quite wrap my head around this.

Thanks!
srry if i posted in the wrong section

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[jta7]

should of learned in school

2n^2

 

[iliveinmyguitar]

I forgot to mention, I get that you can use 2n^2 but isnt zinc a n=3 atom? isn't its number of electron 30?

 

[HCHopeful]

n=1 has 2 electrons, n=2 has 8 electrons, n=3 has 18 electrons. Zinc may be in the n=3, but it includes n=2 and n=1 as well. This gives 28 electrons. OH NO! WHAT HAPPENED TO THE OTHER TWO?! Oh yeah, you have to fill up to the 4s (2 electrons) orbital before going to 3d, so therefore, 30 electrons in zinc.

I hope this is right haha... I don't really know. It was my logic and seems to make sense.

 

[jta7]

OP, what is the original question? with Zn write out the electron configuration...

 

[SN2ed]

Thread closed. These types of questions belong in the MCAT Study Q&A forum only.