Nomenclature of the Radicles    Part IV

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Look at these two diagrams:

Each has a long chain of carbon atoms.
In both cases the chain consists of (how many?) _______ carbon atoms.

Look at the left-hand diagram.
You know the name of this compound. It is _______

Look at the right-hand diagram.
The diagram is the same as for butane except that one of the
hydrogen atoms has been replaced by a little group of atoms
consisting of ________
But we already know that such a group whether it is arranged this way:
or this way  or this way 

is called the ________ radical.
What we have, then, is a sort of butane with a
methyl radical replacing one of the hydrogens.
Or, to say it another way, we have some kind
of _________ butane. 

177.                                                                                             four
                                                                                                    1 carbon and 3 hydrogens
Now to find out how to name this
It is considered that such a radical is attached
to a certain one of the four carbon atoms.
Draw the four-carbon chain, with its single bonds,
and number each carbon beginning at the left.
Then number them again, beginning at the right. ______ 

This is the diagram for the compound we are to name:

The name of the compound is 2-methyl butane.
"Butane" is part of the name because _______. 

                                                           The compound is basically the
                                                           butane formula, with four carbons.
"Methyl" is part of the name because _______ 
                                                         There is a methyl radical instead

                                                         of a hydrogen attached to one
                                                         of the carbons.
"2" is part of the name because
(notice where the radical is attached) ________ 
                                                             The methyl radical is attached to

                                                             the second carbon atom from the
                                                             left, in the diagram.
Now look at this diagram:

It is somewhat different from 2-methyl butane.
There are (how many?) atoms in the main chain of carbon atoms._______ 

There is a methyl radical, but it is attached to the
carbon atom that is placed ________. 
180.                                                                                               third from the left

A compound in the methane series that has six carbons
with single bonds between them is named __________. 
181.                                                                                                 hexane

But when a certain hydrogen atom in hexane is replaced
by a methyl radical, the compound is some sort of ________ hexane. 
182.                                                                                                 methyl

To find the exact name, we must describe the position of
the carbon atom to which the methyl radical is attached.
Correctly numbered, the carbon chain looks like this:

The methyl radical is attached to the third carbon from the left.
The number of that carbon is 3, beginning from the left,
or 4, beginning from the right.

There is a rule: When you have a choice of numbers for
describing a radical always choose the smallest.

Therefore, the name of this kind of methyl hexane is ________ 

183.                                                                                           3-methyl hexane
Suppose the formula had been written thus:

This arrangement shows the methyl radical
above its attachment to the carbon atom.
Would that have changed the name?
No, it would still be attached to the 3,4 carbon atom,
and its name would still be ________ 
184.                                                                                     3-methyl hexane

Look at this diagram:

The longest chain has (how many?) ________ carbon atoms? 

The compound is some sort of ___________
185.                                                                                                 octane

Look at the radical attached to the carbon chain.
It is not a methyl radical,
which we write in this way: CH3-
Write the formula of this new radical in a similar way ________ 

The name of the radical is the _________ radical 
186.                                                                                                  ethyl

The compound is, then, some sort of ethyl octane.
We will complete the name by numbering the carbon atom
to which the ethyl radical is attached.

Number the chain of carbon atoms, remember the rule
about numbering and write the name of the compound _________ 

187.                                                                                               4-ethyl octane
Did you make an error?  The carbon atom was fifth from the
left and fourth from the right.  The rule is that when you have
a choice of numbers, you use the ___________
188.                                                                                              smaller number

Here is a different formula. Don't worry about the extra-long
lines that represent bonds between the carbon atoms in the chain.
They are still just single bonds, but more room is needed to
write in the rest of the diagram.

The longest carbon chain contains (how many?) carbon atoms _________ 

Therefore the compound is some kind of __________ 
189.                                                                                                    pentane

Attached to the chain are two _________ radicals 

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