 Organic molecules contain both carbon and hydrogen. Though many organic chemicals also contain other elements, it is the carbon-hydrogen bond that defines them as organic.  Organic chemistry defines life. Just as there are millions of different types of living organisms on this planet, there are millions of different organic molecules, each with different chemical and physical properties.

 All organic chemistry is based upon unique properties of the carbon atom.  Carbon, C, hybridization to sp 3 orbitals, carbon can now form 4 bonds

 The ground state, or unexcited state, of the carbon atom has the following electron configuration.  Covalent bonds are formed by the sharing of electrons, so ground-state carbon cannot bond because it has only two half-filled orbitals available for bond formation.

 Adding energy to the system promotes a 2 s electron to a 2 p orbital, with the resulting generation of an excited state.  The excited state has four half-filled orbitals, each capable of forming a covalent bond.

 Hybridization is the combination of two or more atomic orbitals to form a new set of atomic orbitals.  The combination of one 2s atomic orbital and three 2p atomic orbitals forms four equivalent sp 3 hybrid orbitals.  Because they are derived from four atomic orbitals, sp 3 hybrid orbitals always occurs in sets of four.  This is why carbon can now form four bonds.

Carbon always has to be covalently bonded on four places. The simplest organic chemical is CH 4 ·

1. Meth ane CH 4 2. Eth ane CH 3 CH 3 Hydrocarbons that contain only carbon and hydrogen and single bonds are called alkanes. Alk anes always end in ane. The prefix tells how many Carbon atoms are in the compound

 The prefix tells how many carbon atoms are in the compound. PrefixNumber of Carbons Meth1 Eth2 Prop3 But4 Pent5 Hex6 Hept7 Oct8 Non9 Dec10

1. Methane CH 4 2. Ethane CH 3 CH 3 3. Propane CH 3 CH 2 CH 3

1. Methane CH 4 2. Ethane CH 3 CH 3 3. Propane CH 3 CH 2 CH 3 4. Butane CH 3 CH 2 CH 2 CH 3

1. Methane CH 4 2. Ethane CH 3 CH 3 3. Propane CH 3 CH 2 CH 3 4. Butane CH 3 CH 2 CH 2 CH 3 5. Pentane CH 3 CH 2 CH 2 CH 2 CH 3

1. Methane CH 4 2. Ethane CH 3 CH 3 3. Propane CH 3 CH 2 CH 3 4. Butane CH 3 CH 2 CH 2 CH 3 5. Pentane CH 3 CH 2 CH 2 CH 2 CH 3 6. Hexane CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 7. Heptane CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3

1. Methane CH 4 2. Ethane CH 3 CH 3 3. Propane CH 3 CH 2 CH 3 4. Butane CH 3 CH 2 CH 2 CH 3 5. Pentane CH 3 CH 2 CH 2 CH 2 CH 3 6. Hexane CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 7. Heptane CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 8. Octane CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 9. Nonane CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH Decane CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3

 Hydrocarbons that contain only carbon and hydrogen and only single carbon bonds are called alkanes.  Hydrocarbons that do not contain rings are called aliphatic compounds  Alk anes end in ane and the prefix tells you how many carbon atoms are present in the longest chain.  Number chains so that you end up with the longest possible chain.

 The molecular formula of butane is C 4 H 10  The structural formula of butane is CH 3 CH 2 CH 2 CH 3  The display formula for butane is HH H H C CCC H HHH H H │ ──── │ │ ││ │ ││ ─

 Propane  C 3 H 8 Molecular Formula  CH 3 CH 2 CH 3 Structural Formula

 Molecular Formula:C 6 H 14  Structural Formula: CH 3 CH 2 CH 2 CH 2 CH 2 CH 3  Name: Hexane

 Display Formula:  Ethane  C 2 H 6 (Molecular Formula)  CH 3 CH 3 (Structural Formula)