Chapter 1 Vocab

Question 1

curved-arrow formalism

Answer 1

A method of drawing curved arrows to keep track of an electron movement from nucleophile to electrophile (or within a molecule) during the course of a reaction

Question 2

delocalized charge

Answer 2

A charge which is spread out over two or more atoms. We usually draw resonance forms to show how the charge can appear on each of the atoms sharing the charge.

Question 3

nucleophile

Answer 3

an electron pair donor

Question 4

resonance hybrid

Answer 4

A molecule or ion for which two or more valid Lewis structures can be drawn, differing only in the placement of the valence electrons.

Question 5

major contributors

Answer 5

The more important (lower-energy) structures

Question 6

minor contributors

Answer 6

The less important (higher-energy) structures)

Question 7

normal covalent bond patterns for carbon

Answer 7

Question 8

normal covalent bond patterns for nitrogen

Answer 8

Question 9

normal covalent bond patterns for phosphorous

Answer 9

Question 10

normal covalent bond patterns for oxygen

Answer 10

Question 11

normal covalent bond patterns for sulfur

Answer 11

Question 12

normal covalent bond patterns for halogens

Answer 12

Question 13

Alkanes

Answer 13

Single bonds between all carbons.

Question 14

Cycloalkanes

Answer 14

Single bonded carbons that form a ring.

Question 15

Alkenes

Answer 15

Double bonded carbons are present in the molecule.

Question 16

Cycloalkenes

Answer 16

Double bond in a ring.

Question 17

Alkynes

Answer 17

Triple bonds are present in the molecule.

Question 18

Aromatic

Answer 18

Contains a phenyl ring.

Question 19

The ‘R’ Group

Answer 19

• Organic chemists use a capital ‘R’ as chemical shorthand to represent an undefined carbon-based structural fragment
• Representing part of a compound as ‘R’ shifts our attention away from the unimportant portions of the molecule and focuses our attention on the functional groups

Question 20

What atoms are involved in resonance?

Answer 20

Only atoms with lone pairs, multiple bonds, and incomplete octets are involved in resonance.

Question 21

In the case of positive charges, how do you determine which structure is the major contributor?

Answer 21

With positive charges, the structure with complete octets is the major contributor

Question 22

Conjugated Systems

Answer 22

alternating single + multiple bonds

Question 23

Steps for drawing Line Angle Formulas

Answer 23

1) C atoms are implied wherever there is a change in angle

2) Hide H’s on C (keep them everywhere else)
3) Bonds to H are not shown (OH instead of O-H)
4) Hide non-bonded electrons (lone pairs)

Question 24

What is the shortcut for finding molecular formulas of fully saturated, acyclic alkanes?

Answer 24

C_nH_(2n+2)

Question 25

What does a low pKa indicate?

Answer 25

Low pKa = strong acid

High pKa = very weak acid

Question 26

pKa + pKb

Answer 26

pKa + pKb = 14

Question 27

How does resonance affect bases?

Answer 27

More resonance = more stable = weaker base

Less/no resonance = less stable = stronger base

Question 28

How do electronegative atoms in a structure affect acidity/basicity?

Answer 28

A more electronegative element bears a negative charge more easily, taking away electrons from hydrogen and making it more positive - thus it gives up the hydrogen more easily and is a stronger acid.

Question 29

How does size affect acidity/basicity?

Answer 29

Acids - As size increases, the H is more loosely held and the bond is easier to break - making acids with larger size stronger.

Bases - As size increases, the anion becomes more stable - making it a weaker base. With a small size, there is a lot of electron repulsion, making the anion less stable and thus a stronger base.