Alkenes and Alkynes (Double & Triple bonds)

Alkenes and Alkynes (Double & Triple bonds)

-Each carbon can have 4 bonds:

 Carbon can form double & triple bonds with carbon atoms, when multiple bonds form, fewer hydrogen will attach the carbon atom

-The position of the double/triple bonds always has the lowest number and is put in front of the parent chain. Ex.

2-pentene

1-pentene 

-Naming rules are almost same as Alkanes, just change –ane to –ene foe Alkenes

For example CH2=CH2 ehene CH2=CH–CH3 1-propene or propene

-as we know, the general formula for Alkanes is C_nH_{2n+2 ,} here have another formula for Alkenes  is C_nH_2n

Naming rules:

1) Find the longest chain and place it at the end of the name

2) Number the carbon atoms to get the lowest number for the start of the double bond and place that number before the parent name.

3) Assign names and numbers for all side groups and assemble the name alphabetically (videos)http://www.youtube.com/watch?v=KWv5PaoHwPA

Alkenes: some molecules will have the same structure, but have different geometry.-these called geometric isomers

-          trans & cis butane  eample:

.

1. If the larger groups are both above H or below R the plane of the bond, the double bond is termed a “cis” double bond

2. If the larger groups are across the plane of the bond (H or R), the double bond is termed a “trans” double bond

3. If there are two identical groups on either end of the double bond (H or R), there are no geometric isomers, and no need for cis or trans in the name

Alkynes (hydrocarbons)- triple bonds between carbon atom  (-yne for alkynes)

-Naming rules: (general formula: C_nH_2n-2)

The naming rules are “mostly” the same as the alkenes (with no cis or trans!)

1) Find the longest chain (and write at the end)

2) Number the carbon atoms to get the lowest number for the start of the triple bond and write that number before the parent name

3) Assign names and numbers for all side groups and assemble the name alphabetically

Double bonds (Alkenes) end in –ene Triple bonds (Alkynes) end in -yne

http://www.youtube.com/watch?v=CJYzbs_vyUs

Bohr Models and Diagrams

Bohr (1920)

1. Protons and electrons attract each other, so that Rutherford’s models are unstable. When matter is heated, it will emit light.
2. .Light travels as photons (wavelength)
3.  Each atom has different spectra of light

Bohr based his model on the emission of light. To explain this, he presumed some theory:

1. Electron exist in orbital or shells
2.  Because matter is unstable. When they absorb energy, they move to a higher orbital. When they release energy, they move to a lower orbital.

Protons=11    Atomic Mass= 23.0  

Neutrons=23-11=12      (one valence electron) - so sodium always form an ion with 1+ charge

- Two different models can be used to describe electron configuration:

1. Energy Level Model

2. Bohr Model

-Here are some rules about how electrons occupy shells:

1. 2 e- in the first orbital
2.  8 e- in the second orbital
3.  8 e- in the third orbital

-the electrons were absorbing and then emitting energy from different energy levels around the atoms and proposed his model of the atom

http://www.youtube.com/watch?v=-YYBCNQnYNM&feature=related

Organic Chemistry--Functional Groups

Functional Groups are organic compounds can contain elements other than C and H.

Ex. Alcohols, Halides and Nitro, Aldehydes, Ketones

Halides and Nitro Compounds

- they can be attached  to alkanes, alkenes, and alkynes

- add the following prefixes in front of the main chain:

F: fluoro

Cl: chloro

Br: bromo

I: iodo

NO2: nitro

Ex. 1, 2, 3-trichloropentane

Alcohols

- contains an -OH functional group

- when naming an alcohol, use the longest chain that contains the OH group

- the "e" ending in the parent hydrocarbon is replaced by "ol"

Ex. 3-ethyl-2-pentanol

- If there are more than one -OH group, add -diol, -triol, etc. endings

Ex. 1,2-butanediol

Aldehydes:

- a compound that contains a double bond oxygen at the end of a chain

- change the parent ending to "-al"

Ex. propanal

Ketones:

- a compound that contains a double bond oxygen that is not on either end

- add "-one" ending to the parent hydrocarbon

Ex. 4-methyl-3-heptanone

May 26--Organic Chemistry

Organic Chemistry -- The chemistry of CARBON compounds.

Some of the examples in our everyday life:

clotting--polyester

plastic--polyethyiene

Organic Compounds properties:

1.  low melting points

2.  weak or non-electrolytes

3.  can form chains of CARBON atoms that are linked in a

         STRAIGHT LINE, CIRCULAR PATTERN and BRANCHED PATTERN.

Three types bonds:single bond, double bond, and triple bond.

Alkanes(unbranched)

1. Hydrocarbon compounds

2. Non-polar molecules

3. Tetrahedron Geometry

Naming Alkanes :ends with "-ane"

Examples:

Ethane

 Names of Alkanes(needs to memorize!)



Methane   CH4	Hexane     C6H14
Ethane    C2H6	Heptane    C7H16
Propane   C3H8	Octane     C8H18
Butane    C4H10	Nonane    C9H20
Pentane   C5H12	Decane    C10H22

* An easy formula to memorize the above  CNH2N+2

Branched Hydrocarbon

Hydrocarbons can have branched which are also hydrocarbon chains. They are also called subsitituted Hydrocarbon or Branched Hydrocarbons.

Alkyl group is an alkane which has lost one Hydrogen atom and replace by other alkyl group.

Example:

2,2,4-Trimethylpentane

If there have more than one of the same kind of Alkyl group, then use the prefix--"di", "tri"

Example:



Alkyl Groups

Methyl--CH3

Ethyl--CH2-CH3

Proply--CH2-CH2-CH3

Butyl--CH2-CH2-CH2-CH3

Pentyl--CH2-CH2-CH2-CH2-CH3

....

Last but not least, we have two videos that could help you get a better understanding of naming and drawing Alkane hydrocarbon .