Subject: How many electrons are in iron's valence orbital?

I understand the first orbital as being 2 the next as 8, and the next as 8, but 
after that, I don't see how the orbitals can continue to be 8 with how the 
periodic table is set up.  My book says the octet rule means the atoms can only 
have no more than 8 electrons in their valance orbital. There are 10 extra 
elements when you get past the first three periods. According o the periodic 
tlbe, iron would have eight but is not a noble gas.  Thank you for your help.

Re: How many electrons are in iron's valence orbital?