00:01
To determine the configuration of each of the following molecules, what we're going to start with is we're going to rank the groups in order of increasing priority.
00:10
So number one will be have the highest priority, number four be the lowest.
00:13
So starting with part a, this group of the top has the highest priority.
00:19
Next we have the ch2br.
00:23
And next we have the ch3, ch2, and lastly we have our ch4.
00:28
Now, if we were to draw an arrow from 1 to 2 and 2 to 3, it would be in the clockwise direction.
00:39
So therefore, it is our configuration.
00:43
For part b, the group with the highest priority will be our oh group, since oxygen has a higher atomic number, than the carbon or hydrogen.
00:52
Next, we have the c .h2 .o .h.
00:56
Next, we have the group of the top, and lastly, we have the hydrogen.
00:59
Again, if we drew arrows from 1 to 2 and 2 to 3, it would be in the counterclockwise direction, suggesting it's s configuration.
01:08
However, there's a rule that states that if our lowest priority group, in this case the hydrogen, is on the horizontal part, so it's horizontal of the diagram, the answer will be the opposite.
01:22
So even though drawing arrows from 1 to 2 and 2 to 3 would suggest that the configuration is s, since it's counterclockwise, the answer is actually r, since the hydrogen is not on a vertical arm...