Carbon Bonding

· Carbon has 4 valence electrons. This number of valence electrons allows carbon to have a variety of bonding configurations to complete its octet of electrons.

· Carbon can bond to many other elements as well as to other carbon atoms to form long chains.

· Carbon containing compounds are called ORGANIC compounds. These are the compounds that make up living things.

· Some examples:

Carbon Can Form Long Chains

· One way for carbon to complete its octet is to form long chains with other carbon atoms.

· When the chains contain carbon atoms and hydrogen atoms, these molecules are called hydrocarbons.

· Hydrocarbons can contain single, double or triple bonds between the carbon atoms.

Hydrocarbons that contain carbon and hydrogen with only single bonds are called alkanes.

Hydrocarbons that contain carbon and hydrogen with double bonds are called alkenes.

Hydrocarbons that contain carbon and hydrogen with triple bonds are called alkynes.

Hydrocarbons that have the maximum number of hydrogen atoms bonded to carbon are said to be SATURATED. These are the hydrocarbons that ONLY have single bonds (alkanes).

Hydrocarbons that have double or triple bonds (alkenes and alkynes) are said to be UNSATURATED as they have fewer than the maximum number of hydrogen atoms bonded to carbon.

The Name of an alkane, alkene, or alkyne indicates the number of carbons

For instance, propane has 3 carbons and all single bonds.

Pentene would have 5 carbons with one double bond. The location of the double bond is typically indicated by a number that represents the carbon in the chain where the double bond starts.

2-pentene would have 5 carbons in a chain with the double bond between the 2nd and 3rd carbons in the chain.

Carbon has More than 1 Elemental Form

Certain elements have ALLOTROPES. An ALLOTROPE is a when the same element can be bonded in different ways producing forms of the element with different properties.

Carbon has 3 different allotropes.

Structural Isomers

Organic compounds with multiple carbon atoms can bond in more than one way but have the same formula. These are called Structural Isomers.

These types of isomers are only seen when there are 4 or more carbon atoms in the chain. Look at butane below. Both of these have the formula, C4H10

However, they are different compounds, with different names and different properties.

Carbons are often numbered to distinguish one carbon from another in a compound.

Functional Groups

Groups of atoms can be substituted for hydrogen in organic compounds. These groups are called Functional Groups.

The addition of functional groups alters the chemical properties of the compound. Many organic compounds that you are familiar with contain these functional groups.

The table that follows lists some common functional groups that can be substituted for hydrogen in any alkane, alkene or alkyne.

The ‘R’ stands for any carbon chain. The points where the lines meet or where a line ends represents a carbon atom in the following structures (unless otherwise indicated).