How is the electron configuration of iodine determined?

[eddieberto]

the question is
Write both the complete electron configuration and the noble-gas notation for iodine,I, How many innershell electrons does an iodine atom contain?





my answer to the first question is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 4d^10 then i get lost

 

[Bohrok]

You need to review the http://en.wikipedia.org/wiki/Electron_configuration#Aufbau_principle" so you have the subshells in the correct order.

Noble-gas notation begins at the last noble gas before the element you're doing the electronic configuration for, then do the electronic configuration beginning after that noble gas.

I'm not sure about innershell electrons...