Using only the elements Ca, Cl, and Si, give formulas for the following. (b) A molecular compound with polar covalent bonds that obeys the octet rule and has no formal charges

Video transcript

Hello everyone today. We have the following problem using only chlorine and floor een draw the structure of a compound with an expanded octet and two lone pairs on chlorine and zero formal charges. So first we need to determine out of chlorine florin, which one will have the expanded octet. So out of these two it's going to be chlorine. So chlorine can expand its octet because it has an empty D orbital and this essentially implicates that electrons can be quote unquote dumped into that orbital if need be so chlorine usually will form one bond however, if need be, it can form five bonds And so we'll keep that in mind that it can form five bonds. Flooring on the other hand, can only form one bond And that is the case for most or all of our group seven a elements. So we need to determine how many valence electrons we have to construct our diagram. So valence electrons are determined by the group number that we have. So we have chlorine here and we have flooring here Starting off we'll have seven valence electrons for each. And we need to determine how many additional ones will have to add. So it says here that we'll have to have two lone pairs on chlorine and zero formal charges to calculate for formal charge will say the formal charge for our flooring to start that's going to be the number of valence electrons minus, how many bond lines that flooring has minus, how many electrons are surrounding that flooring atom. And so if we can have the valence electrons being seven here, The formal charge has to be zero. We need to talk we and we know that flooring can only form one bond. We know that there's going to be one bond line attached to it. We are now able to solve for the number of electrons that should be around flooring. So if we saw for that, we get that there should be six electrons around a flooring or each of our florins. We're going to keep that in mind. And if we calculate the formal charge of our chlorine, it's going to be the same principle with our valence electrons minus how many bond lines are around that chlorine are connected to it minus the number of electrons. Lone pairs of electrons are in lone pairs of our chlorine. So once again it said, our formal charge has to be zero. The number of valence electron for chlorine is seven because it is a group seven a element bond lines. We're not quite sure we know that I can form five bond lines but we are not 100% sure how many exactly. So that's what we need to solve for this did state that there are two lone pairs on chlorine, which means that equals a total of four electrons since one lone pair equals two electrons, solving for this, we get zero is equal to three minus our bond lines. And essentially we get that we should have three total bond lines on a chlorine. So with this information we can construct our diagram. Our diagram is going to have one chlorine in the middle surrounded by three different florins. And so this obeys the bond line rule that flooring can only form one bond And Chlorine has three bond lines. Now you said florida would have six electrons surrounding it directly, 6123456. So we now fulfilled that as well. And then the question stated that chlorine has to have two lone pairs on it, so we're just going to add one lone pair and two lone pairs. And with that we have constructed our diagram for this problem. Overall, I hope that this helped and until next time.