00:01
For this question, we have three different compounds that we want to determine the lewis structure of, and then using vesper theory, we want to predict what their shape is.
00:08
So first we have carbon tetrafluoride, just cf4.
00:15
So the first thing we have to determine is the number of electrons that we're working with, and we're just looking at the valence electrons.
00:22
So carbon has four valence electrons, and then fluorine has seven valence electrons, and we've got four of them.
00:31
We'll multiply that by four to give us 28.
00:35
And then we'll add the four from the carbon.
00:38
And we've got 32 electrons that we're working with.
00:41
So whenever drawing a lewis structure for covalent compounds, the way that i do it is i first draw our central atom.
00:50
Your central atom is usually going to be the one that's listed first in the compound.
00:54
If it's not the first one listed, generally it's going to be whatever one is in the least quantity because you want to make things look as symmetrical as possible.
01:03
So i draw the central atom, which is carbon, and then i draw the fluorings around it.
01:11
And i go ahead and give everybody all the electrons they want, and everybody wants eight.
01:16
Our lines represent our covalent bonds, and those represent two electrons.
01:20
So carbon already has eight.
01:22
So now we're going to give floring, each flooring six electrons around it, or three lone pairs each.
01:35
So i do that first, and then i go around and count to some.
01:38
See how many electrons we actually have represented.
01:41
If we have too many, then that's when we'll start doing double bonds and then triple bonds.
01:46
But if we have exactly 32 already, then we'll be done.
01:49
So if we count, we'll see that we've got eight electrons here.
01:57
We've got eight here, eight here, and eight here.
02:00
And all together, that ends up being 32.
02:03
So we're actually good to go.
02:04
So this will be our lewis structure for our carbon tetrafluoride.
02:09
And then now to determine the shape using vesper theory.
02:13
What you end up doing is looking at the number of domains on the central atom and the domains are going to include any bonds.
02:20
So a single bond, a double bond or a triple bond.
02:23
Keep in mind a double bond counts as one domain and a triple bond counts as one domain.
02:28
You don't count a double bond as two or a triple bond is three.
02:31
And then any loan pairs are also a domain.
02:34
So carbon's got this bond, this bond, this bond, this bond, and this bond.
02:41
So it's got four domains and it has zero loan pairs.
02:51
So our shape is going to be tetrahedral.
02:59
So now moving to our next compound...