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In this video, we are going to consider the molecule sif4 silicon tetrafluoride, and we want to draw a valid lewis structure.
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So in order to do that, we want to count the number of valence electrons that we have first, and then the number that we want, according to the octet rule, to satisfy the stability.
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And we'll compare the two, and that will determine the number of bonds.
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So we know that silicon is under carbon.
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It has four valence electrons, and there's four fluorines, and each of them has seven valence electrons, like all halogenes, do.
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This is 4 plus 28 is going to be 32 electrons available for bonding.
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Now how much do we want? silicon wants 8 and we have four fluorians and each of them want 8.
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Most elements will want 8 with some exceptions.
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So this 32 plus 8 is going to be 40 electrons.
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The difference between these two when you subtract 40 minus 32, you get 8 electrons and that's how many you'll need to share.
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And if you divide by 2, then you'll get four bonds because each electron, each bond consists of 2.
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Electrons.
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Silicon is less electronegative, so we'll put it in the middle, and then we'll have four bonds.
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Conveniently, we have four fluorine atoms, so that's consistent with one single bond to each fluorine.
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And then we know that in order to satisfy the oxide of fluorine, we'll need three lone pairs on each atom, because one bond is two electrons, and we want eight on each.
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And there's going to be no lone pairs for the silicon atom, because it can't form an expanded octet or anything.
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Then if you look, you have six from the loan pair and one from the bond.
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So this right here is eight electrons.
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And you have four groups of them...