Rings and Cyclones

All carbon bonds have the same reactivity because of something called delocaligation. However, all of the aromatic structures that we have learned about are not as reactive as cycloalkanes, which I will be explaining...

Benzene Rings

 This is an image of a Benzene Ring:

The circle in the center represents the electrons in the benzene ring which are "delocalized". This means that they can change position in the ring and are shared equally.





There are a few rules to follow when naming them:
- Side chains are give the name "phenyl"
- This can be a parent chain or a side chain
- Add "benzene" to end of name

For example:

The structure to the right's name would be:

1,2,4,5-tetramethylbenzene

This is because there are four methyl chains coming off of the 1, 2, 3 and 4 corners. As always, you chose the lowest numbers possible.



Here is a video to help you with Benzene Rings:

Alicyclics and Aromatics

- Many hydrocarbons form ring-shaped structures which are known as cyclic hydrocarbons (Alicyclics) and are named using the prefix "cyclo"

- Their general formula is CnH2n ("n" representing the number of Carbon atoms)

-Alicyclics are more reactive and less stable than straight chains

-Numbering for these can start anywhere, as long as they are the lowest numbers possible

Rules for Naming Cycloalkanes:

1. Count length of chain in ring

2. If only one side group, no number needed because it is assumed to be one

3. Cycloalkanes named like straight chain side group, except "cyclo" added to beginning of name

*Give the lower number to the side group that comes first alphabetically*

Cycloalkenes and Cycloalkynes

- More reactive than cycloalkanes

- Similar to cycloalkanes, except ending changed

- *When numbering these, the double or triple bond is always between carbon one and two*

For example:

First of all, you would find the longest chain of carbons. This would obviously be the hexene. It is in a ring, though, so it would be cyclohexene. If you then number all of the carbons, the smallest sequence for the methanes would be 1, 2, 4 and 5. The propyl group's number would be 3. If you put this all together you get:

1,2,4,5-tetramethyl-3-propylcyclohexene

AND THAT'S IT! LAST BLOG OF THE YEAR! YOU ARE NOW AN EXPERT CHEMIST! Well, in grade 11 chemistry, but oh well.

To celebrate this great achievement, I will put a bunch of videos with examples of organic compounds and how to name them. If that isn't ending the year with a bang, I don't know what is.

Ok, so after all that, you must ACTUALLY be a genius now, right?

More Functional Groups: Carboxylic Acids, Esters, Ethers, Amines

Carboxylic Acids, Esters, Ethers, and Amines

Carboxylic Acids

• They are parent chains with a double bonded oxygen and alcohol connected to the end.
• Name is changed simply by adding 'oic' to the end of the parent chains name followed by acid.
• For example: Butane = Butanoic acid

Beautiful Butanoic acid

Esters

• They contain two chains of hydrocarbons separated by an oxygen and double bonded oxygen.
• The parent chain with no double bonded oxygen will be named first and given the ending 'yl'
• The parent chain with the double bonded oxygen will have the ending 'oate'
• For example(picture):

They give off fruity smells.

Ethers

• They consist of 2 groups connected by an oxygen in the middle.
• The shorter group is named first and ends with an 'oxy' ex: methoxy
• The other group will remain the same.

Nice and simple, Methoxybutane

Amines

• They are parent chains with NH2 connected somewhere to it.
• For naming simply add 'yl' then amino. ex: methyl aminoethane

Basic structure of an Amine

Functional Groups: Halides, Nitro, Alcohols, Aldehydes, Ketones

Halides(Nitro), Alcohols, Aldehydes, and Ketones

Functional groups contain elements other than Carbon and Hydrogen. (ex: oxygen, flourine, alcohol, etc.)

Halides(Nitro)

• These can be attached to Alkanes, Alkenes, and Alkynes.
• They are Halogens: Fluoro, chloro, bromo, iodo, etc.
• To name Halides count the positions of the halogens connected to the parent chain.
• Remember, alphabetical order!

an example of a halide would be:

2-Chloro-3-fluoro-pentane

TNT is a Nitro.

Alcohols

• With alcohols the parent chain's name ends with an 'ol' ex: Ethanol
• Again, count the position of the alcohol connected to the parent chain

Here's propanol

Aldehydes

• They are double bonded oxygen connected to the end of the parent chain.
• When naming, the parent chain's end with an 'al' ex: Methanal

A simple methanal.

Ketones

• Basically the same as Aldehydes EXCEPT, the double bonded oxygen is connected in the middle of the parent chain.
• As usual the ending of the parent chain will change this time to 'one' ex: butanone

Glorious Butanone

Organic Chemistry: Naming + Alkanes, Alkenes, and Alkynes

All things organic need a name.

• The differences with each group is how the name ends, in this case Alkanes end with an 'ane'.

Methane!

• Depending on how many hydro Carbons there are the beginning of any name would start with:       -Methane, Ethane, Propane, Butane, Pentane, Hexane, Heptane, Octane, Nonane, and Decane. (these are also all Alkenes!)

A helpful little chart for naming groups of atoms.

Alkenes

• Just like Alkanes, Alkenes end with an 'ene'
• The difference with Alkanes is that it has a double bond somewhere in the chain.
• When counting Alkenes always make note that the double bond should be the lowest number infront of the parent chain.
• An example of an Alkene would be CH2=CH2, ethene

Examples of Alkenes.

Alkynes

• Just like the other two, Alkynes end with an 'yne'
• This time alkynes have a triple bond somewhere in the chain.
• Just like Alkanes, Alkynes should have the triple bond be the lowest number infront of the parent chain.
• An example of an Alkyne would be CH=CH, ethyne

Examples of Alkynes.

The Very Special/Valence Shell Electron Pair Repulsion Theory

The Valence Shell Electron Pair Repulsion Theory, or VSEPR, is a theory based upon the idea that

a. molecules take up three-dimensional space, obviously, and
b. that electrons repel one another.

The result is a series of diagrams which occur, given a certain number of bonded elements as well as unbonded pairs of electrons...

Such special geometric molecules can be specially named:

Where
A represents the central atom,
X# represents the number of outer bonded atoms,
and
E# represents the number of lone electron pairs.

Here is a table of different geometries of different chemical compounds you ought to know for our test!




If you find yourself, daring to ask why they form these interesting shapes. Don't worry, the answer is simple.  Because electrons repel each other in 3D space, each bonded or lone pair of electrons will simultaneously try to space themselves out to create the least amount of repulsion possible.

Watch the video if

a. you're extremely bored.
b. VSEPR Theory still confuddles you.
c. you want to watch a video that concisely demonstrates VSEPR in a way words and pictures cannot.