When determining valence electrons, what are the sublevels that you must consider?

With what we have already discussed, you might realize that just as electron configurations can be used to explain the shape and organization of the Periodic Table, the shape and organization of the Periodic Table can, in turn, be used to predict electron configurations. In fact, if you can locate an element on the Periodic Table, you can use the element's position to figure out the energy level of the element's valence electrons 

Ithink it’s carbon dioxide