Knowing that oxygen likes to form two bonds and that carbon
likes to form four bonds and that hydrogen likes to form one
bond, take a moment and draw two Lewis structures (isomers) given
the formula C2H6O.
Answer
The two arrangements are,
If we write this structure using condensed
formula it would look like, CH3OCH3.
The oxygen atom in this structure is bonded to two carbon atoms. When oxygen is bonded to
two carbon atoms the compound type is called an ether. We say the
R-O-R arrangement is an ether functional group. Here R- is the
abbreviation for an organic group with an available carbon bond.
Well that is one structure...what is the
other??? The other structure must use the same atoms, but the
arrangement of the atoms is different. How could we change the
arrangement? In this arrangement we have the oxygen atom between
the two carbon atoms. The other arrangement we will move the
oxygen between a carbon and a hydrogen atom. So it would look
like,
It does not make any difference which carbon and
hydrogen we choose they are all the same. This is a different
arrangement of the same atoms. In this case the oxygen atom is
bonded to one carbon atom and one hydrogen atom. This compound is
called an alcohol. We say the R-O-H arrangement is an alcohol
functional group. If we write this as a condensed formula is
looks like C2H5OH or CH3CH2OH.
We now know two important functional groups,
ether and alcohol.