[HolyCow]

now its not that i cant form lewis structures, but i was revewing the rules for oxidation states, and i bumped on this example Cr2O7 2- and tryd to find the lewis formula, i spent houres, eventually i found it - so i think - but actually i really dont know how to get that properly; for example when i look on my pse i found 6e- on the outside orbital for oxygen, but for Cr 1 e- on the outside orbital and on the previous 13, now what do i do with that???

[AWK]

http://www.chemistry.wustl.edu/~edudev/LabTutorials/PeriodicProperties/Ions/ions.html