Alkenes and Alkynes

There are unsaturated hydrocarbon compounds that are either connected by double bond or triple bond.  Alkenes are the ones bonded by a double bond and alkynes are the ones bonded by a triple bond.  For alkenes the root names give the number of carbons in the longest continuous chain. Alkene names are formed by dropping the "ane" and replacing it with "ene".  It is written with this formula: CnH2n.  For alkynes the root names give the number of carbons in the longest continuous chain. Alkyne names are formed by dropping the "ane" and replacing it with "yne".  It is written with this formula: CnH2n-2.

A table for alkenes:
No. of
Carbons

 Root Name

 Formula
CnH2n

 Structure

 2

 ethene
 C2H4  CH2=CH2

 3

 propene
 C3H6  CH2=CHCH3

 4

1-butene
 C4H8  CH2=CHCH2CH3

 5

 1-pentene
  C5H10  CH2=CHCH2CH2CH3

A table for alkynes:

No. of
Carbons

 Root Name

 Formula
CnH2n-2

 Structure

 2

 ethene
 C2H2  CH=CH

 3

 propene
 C3H4  CH=CHCH3

 4

1-butene
 C4H6  CH=CCH2CH3

 5

 1-pentene
  C5H8  CH=CCH2CH2CH3

Here is a video explaining name both alkenes and alkynes:

Alkanes

Alkanes are chemical compounds composing of only carbon and hydrogen atoms by single bonds.  The image above is the most simple alkane, methane.  This means that the compound contains 1 carbon atom and 4 hydrogen atoms.  The trend for the other compounds is increasing the number of carbon atoms.  Since the first one is methane with 1 carbon and 4 hydrogen, the next compound would be ethane which contains 2 carbon and 6 hydrogen.  As you gain more carbons, the number of hydrogen is 2 more. 
Here is a table of the simple alkanes:

# Carbon Name Molecular
Formula
Structural
Formula
Methane  CH4  CH4 
Ethane  C2H6  CH3CH3 
Propane  C3H8  CH3CH2CH3 
Butane  C4H10  CH3CH2CH2CH3 
Pentane  C5H12  CH3CH2CH2CH2CH3 
Hexane  C6H14  CH3(CH2)4CH3 
Heptane  C7H16  CH3(CH2)5CH3 
Octane  C8H18  CH3(CH2)6CH3 
Nonane  C9H20  CH3(CH2)7CH3 
10  Decane  C10H22  CH3(CH2)8CH3 















Here is a video:

Bohr Model

The image above is the picture of the bohr model for Cl.  The bohr model shows the electron levels of the element that you want to draw.  Just find out how many electrons are in the element and then fill in the number of electrons in the proper shell.  There are limits for each shell.  They follow as:
1st shell : 2 electrons max
2nd shell : 8 electrons max
3rd shell and all others : 8 max

For example carbon has 6 protons and since we are drawing a carbon atom without a charge it has a overall charge of 0.  This means that there are 6 electrons.  The bohr diagram will look like:
Here is a video:

Lewis Diagrams

What is that picture? That is the lewis structure model of H2O, water.  This diagram shows the bonding between atoms of a molecule and the pairs of electrons that exist within the molecule.  This diagram is used to for showing covalently bonded molecules and compounds. 

To draw this, you have to follow these steps:
Step 1: Count up the number of valence electrons for each atom, and total them up to give the total number of electrons for the molecule

Step 2: Determine which atom is the central atom and join all the atoms using only single bonds. Sometimes which atom is the central atom is hard to determine

Step 3: Add lone pairs to each atom as necessary so that each atom has an octet (except H which can only have 2 electrons total) when you count all the atom's lone pairs and two electrons for each of its bonds.

Step 4: If the total you got in Step 1 is the same as in Step 3, you're done! If it doesn't you'll need to make some changes. If the number of electrons in Step 3 is larger than in Step 1, you must add double bonds as necessary between atoms. Then adjust the number of lone pairs again so that each atom has an octet. **Remember no double bonds to H or with any of the halogens!** If the total electron count with only single bonds is smaller than in Step 1, you probably made a mistake somewhere. Go back and double check.

Step 5: Continue adjusting the arrangement of single and double bonds and lone pairs (and also triple bonds if necessary) until the total electron count matches what you got in Step 1.

Here is a video: