Electronic configuration and the periodic table I came across the following question:


  If each orbital can hold a max. of 3 e–  what is the number of elements in the 4th period of the periodic table? 


I was unable to even start the thought process of answering the question because I'm rather horrible at discerning the period number using the electronic configuration, the number of elements that can be accommodated in a period etc. If someone could please explain it to me, that would be so great, especially since I've googled this too many times already and haven't been able to wrap my head around it yet! 

Thanks in advance :) Cheers!
In the 4th period of the periodic table there is 1 s orbital, 3 p orbitals, and 5 d orbitals. That's a total of 9 orbitals. $9 \times 3=27$

That's 27 elements.