CARBON AND MOLECULAR DIVERSITY

1. CHAPTER 4 CARBON AND MOLECULAR DIVERSITY

2. THE IMPORTANCE OF CARBON • ORGANIC CHEMISTRY-focuses on the study of carbon • ORGANIC MOLECULES-contain carbon • VITALISM-early 19th century; belief in a life force outside the jurisdiction of chemical/physical laws • MECHANISM-shift from vitalistic thought; belief that all natural phenomena are governed by physical and chemical laws

3. CARBON ATOMS:VERSATILE MOLECULAR BUILDLING BLOCKS • THE CARBON ATOMS: • Usually has an atomic number of 6 • Therefore it has 4 valence electrons • Completes its outer shell by forming 4 covalent bonds • TETRAVALENT ELECTRON CONFIGURATIONS • Carbon becomes central figure in large molecules • Carbon can bond easily with many different elements’ • LOOK AT THE FOUR MAJOR ATOMIC COMPONENTS OF ORGANIC MOLECULES

4. ATOMS CARBON BONDS EASILY WITH • HYDROGEN • OXYGEN • NITROGEN • CARBON

5. VARIATION IN CARBON SKELETONS • Covalent bonds link carbon atoms together in long chains that form the skeletal framework for organic molecules. These carbon skeletons may vary in: • LENGTH • SHAPE (STRAIGHT CHAIN, BRANCHED, RING) -NUMBER AND LOCATION OF DOUBLE BONDS THIS VARIATION IN CARBON SKELETONS CONTRIBUTES TO THE COMPLEXITY AND DIVERSITY OF ORGANIC MOLECULES

6. HYDROCARBONS- molecules containing only carbon and hydrogen • Make fossil fuels from long dead organisms • Are hydrophobic because C-C and C-H bonds are nonpolar

7. ISOMERS • ISOMERS ARE COMPOUNDS WITH THE SAME MOLECULAR FORMULA BUT WITH DIFFERENT STRUCTURES AND HENCE DIFFERENT PROPERTIES • THERE ARE 3 TYPES OF ISOMERS • 1) STRUCTURAL-differ in the covalent arrrangement of their atoms • 2) GEOMETRIC-have the same covalent bonding, but differ in spatial relationships • 3) ENANTIOMERS-mirror images

8. 3 TYPES OF ISOMERS

9. FUNCTIONAL GROUPS SMALL GROUPS OF ATOMS THAT ARE BONDED TO THE CARBON SKELETON OF ORGANIC MOLECULES -THEY HAVE SPECIFIC CHEMICAL AND PHYSICAL PROPERTIES -ARE THE REGIONS OF ORGANIC MOLECULES THAT ARE CHEMICALLY REACTIVE -THEY BEHAVE CONSISTENTLY -CREATE UNIQUE CHEMICAL PROPERTIES OF ORGANIC MOLECULES THEY ARE FOUND IN

10. HYDROXYL GROUP • Consists of a hydrogen atom bonded to an oxygen atom, which is in turn bonded to carbon (-OH) • Is a polar group; the bond between O-H is polar • Makes the molecule to which it is attached water soluble • Organic compounds with hydroxyl groups are called alcohols

11. CARBONYL GROUP • CONSISTS OF A CARBON ATOM DOUBLE-BONDED TO OXYGEN (-CO) • IS A POLAR GROUP • FOUND IN SUGARS • ALDEHYDE- THE CARBONYL IS AT THE END OFF THE CARBON SKELETON • KETONE- THE CARONYL IS AT THE END OF THE CARBON SKELETON

12. CARBOXYL GROUP • Consists of a carbon atom which is both double-bonded to an oxygen and single bonded to the oxygen of a hydroxyl group (-COOH) • Is polar and water soluble • The covalent bond between oxygen and hydrogen is so polar that the hydrogen reversibly dissociates as H+. • Since it donates protons, this group has acidic properties • Compounds with this functional group are called carboxylic acids

13. FUNCTIONAL GROUPS • AMINO GROUP AND CARBOXYL GROUP

14. THE AMINO GROUP • Consists of a nitrogen atom bonded to two hydrogens and to the carbon skeleton(-NH2) • Is polar and water soluble • Acts as a weak base. The unshared pair of electrons on the nitrogen can accept a proton • Organic compounds with this functional group are called amines.

15. FUNCTIONAL GROUPS • AMINO GROUP AND CARBOXYL GROUP

16. THE SULFHYDRYL GROUP • Consists of an atom of sulfur bonded to an atom of hydrogen (-SH) • Help stabilize the structure of proteins • Organic compounds with this functional group are called thiols

17. THE PHOSPHATE GROUP • It is the dissociated form of phosphoric acid (H3PO4) • Loss of two proton by dissociation leaves the phosphate group with a negative charge • Has acidic properties since it loses two protons • Polar and water soluble • Important in cellular energy storage and transfer (ATP)