00:01
We are asked to do several things.
00:03
One, describe the type of unit cell for sodium chloride.
00:17
And this is phase -centered cubic.
00:30
Our second question is the number of face -centered chlorine atoms, and that will be six.
00:48
Three is number of corner cl atoms.
00:56
And that will be eight and the number of edge centered four is the number of edge centered n .a.
01:20
Let me get back to this.
01:23
I gotta go find my image again.
01:26
Two, three, four, five, six, seven, eight and that will be twelve and there's one and a in the center.
01:44
So then i have for five, i have number of units of n -a -c -l in the unit cell.
02:05
In order to do that, for my face centered, i'm going to divide this by two, so i get three chlorines.
02:15
And for my corner centered, i'm going to divide this by eight, and i get one.
02:19
So i've got four chlorines.
02:23
For my edge -centered, i'm going to take 12 divided by four, and that gives me three.
02:30
And here one divided by one, that gives me one, so i get four nacls or nas.
02:42
So there are four nacls in a unit cell.
02:48
And then finally it asked me to find the density.
02:56
And i am given the following information, the edge length will be equal to d, which is two times the r of cl minus, plus two times the r of cl minus, plus two times the r of an a plus.
03:22
Both of these are given...