(b) It turns out that ozone, O3, has a small dipole moment. How i...

Question

(b) It turns out that ozone, O3, has a small dipole moment. How is
this possible, given that all the atoms are the same?

Accepted Answer

welcome back everyone. We're told that the molecule ozone will have a small dipole moment even if it's made up of the same atoms and we need to determine which statement below explains this phenomenon. So we're going to begin by drawing out the structure of ozone. However, we need to calculate total valence elek John's first and so we would recognize that because we have three oxygen atoms, we want to multiply by their valence electrons. And recognizing that group number corresponds to a number of valence electrons we find on our product table oxygen located group six a corresponding to six valence electrons. So this would give us a total of 18 valence electrons total. We have three oxygen atoms surrounding each other where we're going to recall the bonding preference of oxygen which is to have two bonds and two lone pairs and counting the valence electrons directly attached to this first oxygen, we would count 123456, which would give it a formal charge of zero. So this oxygen is stable and happy moving on to our number of electrons we view so far, we can count to 46 and eight. So we would count Or subtract eight from our total of valence electrons leaving us with 10 valence electrons left, meaning we can form a single bond between this central oxygen and the third oxygen. To use a total of two more electrons where we would have a total of three lone pairs around this third oxygen. And so that would use a total of 2468 and we would have two valence electrons left to fill in as a lone pair on this central oxygen. So that would leave us with zero. So we've used up all of our valence electrons and this would complete our structure for ozone. Now we want to recognize that this lone pair on our central atom is going to add negative character to our oxygen atom in the center. And so that's going to create a di pole in the upward direction here towards our central atom, which creates a shielding effect. And this is going to contribute to the actual structure of ozone being a tribunal planer geometry. And so drawing that out, we would have our same structure but with a tribunal pyramidal geometry or sorry, tribunal planer geometry, which is why we have this more bent shape here. So as I just stated, we have a bent shape. So this corresponds to our molecular geometry being bent. Whereas our tribunal planner geometry is attributed from our notation where we can recognize that we have on our central atom a total of to directly bonded atoms. So A X two and we would have E for that one lone pair on our central atom here. And this corresponds to tribunal planer geometry notation. Now going back to our prompt, we need to explain the small dipole moment in our structure and as I stated earlier, we have a net die pole that is attributed from the lone pair on our central atom there, which creates uneven electron distribution and a shielding effect contributing to our bench structure of ozone. So again, this is the actual structure of ozone. And so this is why even though we have all the same oxygen atoms making up our molecule, that central oxygen atom having that lone pair is truly contributing to the presence of the dipole moment. And so that would confirm that the only correct choice to complete this example is going to be choice B, which confirms that the lone pair on the central oxygen atom causes an uneven electron distribution within the molecule contributing to that small dipole moment. So B is our final answer. I hope that everything I reviewed was clear. If you have any questions, please leave them down below and I'll see everyone in the next practice video.

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