[NewtoAtoms]

Hello,

I am new to chemistry, so please excuse my questions. 

When drawing a lewis structure for OF2, I understand that both O and F need 8 electrons to be stable.

BUT

When I am drawing the Lewis structure for the chlorate ion, I realize that the central Cl will have 10 e-  Can anyone explain to me why this is???

Any help would be greatly appreciated!!!

New to chemistry..

[Rico]

Hey NewtoAtoms

I see your problem! When you are drawing lewis structures for different molecules or ions you always has to think about resonance structures. Resonance structures is differerent ways of drawing the same molecule or ion, that to some extend reflects the electron-distribution. I have drawn the three most resonable resonance structures for the chlorate-ion (see jpeg attached). As you can see the first resonance structure actually obeys the octet rule, whereas the other two don't (Cl has 10 and 12 electrons respectively). This is very common problem in chemistry, which theories such as VB fail to explain and it is termed hypervalency. Hypervalency is often also observed for elements such as S and P.

I hope this is of help to you

Rico