Find total number of electrons of the valance shells of carbon and oxygen atoms Total electrons pairs Center atom selection Put lone pairs on atoms Check the stability and minimize charges on atoms by converting lone pairs to bonds. 15 juin 2013 · A step-by-step explanation of how to draw the CO3 2- Lewis Dot Structure (Carbonate ion). For the CO3 2- structure use the periodic table to find the total number of valence electrons for.