Which molecule has polar bonds but is nonpolar? (LO 8.6) (a) SF6 (b) SF2 (c) F2 (d) NF3

Video transcript

Hello everyone today. We have the following problem identify the compound that is a non polar molecule but contains polar bonds. So first we're gonna start with our answer choice A which is bro mean try fluoride First. We have to examine what this molecule or what this compound consists of. So we have our own means and we have a Florian's present. Browning is a group seven a. Adam which means that it has seven valence electrons. Flooring is also a group seven a element and also has seven valence electrons. However there are three of them present. So there are a total of valence electrons for that flooring giving us a total Of electrons to construct our Diagram. Something that's important to note is that bro mean forms one bond and flooring also forms one bond due to it being a seven A. A group seven A. Element. So it forms one bond that can help us construct our diagram which is the following. We're gonna have our browning in the middle. We're going to have three florins surrounding it. We're going to draw in our missing electrons since flooring has seven valence electrons, we're going to draw six individual electrons around each flooring and then we have four remaining so we can draw them on our browning. It's also important to note that due to a periodic trend of flooring being more electro negative than browning. In fact flooring is the most electro negative atom. We can go ahead and draw our di pole moments with arrows pointing towards our florins and away from our browning's the third and final step for this answer choice is we have to determine its geometry. So this is known as a T shaped molecule. And in this we can also note that our dipole moments or our arrows don't cancel. So we have polar bonds. However, the dipole moments don't cancel, meaning this is a polar molecule and therefore it is incorrect. It's not the answer we're looking for. Next. We're going to try iodine, pensa, chloride. As usual. We're going to figure out what our compound consists of. We have iodine and we have chlorides. These are both group seven a elements or atoms. And so for iodine for iodine We're going to have our seven valence electrons and our seven advanced electrons for chlorine, however, there are five of them. So then we have 35 electrons for chlorine and in total we have 42 electrons. But we can use to construct our diagram as usual with group 78 elements. iodine and chlorine can only form one bond. And so this essentially means that we have our iodine in the center surrounded by five chlorine atoms. Next we're gonna draw our six individual electrons around each of these chlorine since chlorine has seven valence electrons, it has one from the bond line and it needs six additional ones. And then we're gonna go ahead and draw one more lone pair on that iodine. And so this geometry is square pure middle. And so we need to figure out which of these is more electro negative. And according to the periodic trend as electro negativity increases as it goes up into the right of the periodic table. So chlorine is going to be the most electro negative. So we're going to draw our arrows or our dipole moments towards our chlorine. And so we can see that our di polls also don't cancel. So our di pole moments don't cancel, indicating that we have a polar molecule also be is not our answer choice. Next we can move on to see or oxygen gas, oxygen is a group six A element And therefore has six valence electrons and there's two of them. So we have a total of 12 electrons. We can use to construct this Since oxygen is a group a element, it can form two bonds. And so since it's essentially connected to itself, we can go ahead and fill out the rest of our electrons. So we said it has six valence electrons. So each oxygen just needs four additional ones. Since it has two from each of the bond lines. Remember, a bond line has two electrons and one is being given to the oxygen and the other is given being given to the other oxygen. And we have two of those from this, we can note that there are no dipole moments. And why is that? That's because for the geometry this is linear and there's no dipole moments. And since there are no dipole moments, there's essentially no polar bonds at all either. So this is going to be a non polar molecule. So C is going to be incorrect, leaving us with answer choice D. But let's see why D would be correct. We're going to draw D right here and this is going to be our xenon touch of chloride. And so xenon is a group eight A element. So it has eight valence electrons. Chlorine is a group seven a element. So it has seven valence electrons. However, there are four of them. So we essentially have 28 electrons there and in total We have 36 electrons. So in total we have 36 electrons constructing this. We see that we have one xenon. And so it is going to be surrounded By four individual chlorine, drawing in our six electrons for each chlorine. Remember chlorine is a group seven A element. So it needs seven valence electrons. And so it has one already from the bond line. So we need six additional ones. If we examine the geometry, if we examine the geometry, we can see that this is representative of a square planer or square planar molecule, let's look at the dipole moments chlorine according to the periodic table has higher electro negativity than xenon. So their diet holes are going to essentially go towards the chlorine and we can see that they actually cancel out since they're all going in opposite directions. So our di pole moments cancel, indicating this is a non polar molecule, however, it does have polar bonds, and so that is why answer choice D. Is our answer. Overall, I hope that this helped, and until next time.