CHAPTER 4 NOTES I THE IMPORTANCE OF CARBON TO DIVERSITY AND EVOLUTION A Carbon C atoms are versatile building blocks 1 Carbon has 6 electrons with 2 in the first electron shell and 4 in the second shell thus it has 4 unpaired valence e in a shell that holds 8 so it seeks 4 additional e forms 4 bonds 2 Carbon s 3D geometry is a stable tetrahedron that supports covalent bonding with many different atoms B Carbon atoms combine in multiple ways permitting formation of diverse organic molecules 1 The number of unpaired valence e indicates how many chemical bonds an element will form 2 O N Valence 2 Valence 3 Many lengths are possible for C based molecules 3 Double bonds and triple bonds are possible 4 Rotation around C C bonds enable ring shapes C Valence 4 5 Isomers def same molecular formula compounds that have the same numbers of atoms of the same elements but different structures and hence different properties different molecular structure 3 different types structural geometric and enantiomers Structural isomers differ in the covalent arrangements of their atoms Geometric isomers carbons have covalent bonds to the same atoms but these atoms differ un their spatial arrangements due to the inflexibility of double bonds Enantiomers isomers that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon one that is attached to four different atoms or groups of atoms they are important in the pharmaceutical industry a molecular formula of simple sugars C6H12O6 b biological importance shape correlates with function II FUNCTIONAL GROUPS BOND TO CARBON SKELETONS CONFERRING PREDICTABLE CHEMICAL BEHAVIOR TO MOLECULES Functional groups chemical groups on the end of molecules Six functional groups are important to life A Hydroxyl OH B Carbonyl COH C Carboxyl COOH acidic POLAR soluble in water D Amino NH2 basic E Sulfhydryl SH disulfide bonds F PO4 multiple charges Phosphate G Methyl CH3 NONPOLAR wont dissolve in water