4.1 Organic Chemist's Toolbox

Question 1

What is a saturated organic molecule?

Answer 1

contains no pi bonds and no rings; has exactly 2n+2 hydrogens

Question 2

What is an unsaturated organic molecule?

Answer 2

has at least one pi bond or one ring; has fewer then 2n+2 hydrogens

Question 3

What is degree of unsaturation (d) and how is it calculated?

Answer 3

one ring or pi bond in a molecule; calculated by [(2n+2)-x]/2 where n is number of carbon atoms and x is number of hydrogen atoms

Question 4

What is the orbital geometry and hybridization of central atom if you have 2 electron groups?

Answer 4

linear; sp

Question 5

What is the orbital geometry and hybridization of central atom if you have 3 electron groups?

Answer 5

trigonal planar; sp2

Question 6

What is the orbital geometry and hybridization of central atom if you have 4 electron groups?

Answer 6

tetrahedral; sp3

Question 7

What are carbocations?

Answer 7

carbonium ions, positively charge species with a full positive charge on the carbon

Question 8

What are carbanions?

Answer 8

negatively charged species with a full negative charge localized on a carbon

Question 9

What are the two ways organic intermediates are stabilized?

Answer 9

inductive effects
resonance effects

Question 10

What is inductive effect?

Answer 10

stabilization of reaction intermediates by the sharing of electrons through sigma bonds

Question 11

What are electron-withdrawing groups?

Answer 11

groups that pull electrons toward themselves through sigma bonds; tend to stabilize electron-rich intermediates

Question 12

What are electron-donating groups?

Answer 12

donate electron density away from themselves through sigma bonds; tend to stabilize electron-deficient intermediates

Question 13

Are alkyl substituents electron donating or withdrawing?

Answer 13

electron-donating

Question 14

What is a conjugated system?

Answer 14

system containing three or more atoms that each bear a p orbital

Question 15

What are localized electrons?

Answer 15

electrons that are confined to one orbital; either a bonding orbital or a lone-pair orbital

Question 16

What are delocalized electrons?

Answer 16

electrons that are allowed to interact with orbitals on adjacent atoms

Question 17

What are the three basic rules of resonance delocalization?

Answer 17

1. resonance structures can never be drawn for atoms that are truly sp3 hybridized
2. resonance structures usually involve electrons that are adjacent to a pi bond or unhybridized p orbitals
3. resonance structure of lowest energy are the most important