Chad's Prep- Molecular Representations and Resonance

Condensed structures

groups of atoms are clustered together when possible, single bonds are not drawn

The uses of parentheses in condensed structures

1. Methylene groups

2. Long C chains with branches coming off of it

3. Subscript with parentheses for multiple branches

Bond-line structures

All C atoms, and most H atoms, are implied, but not explicitly drawn

• Most common drawing style employed by organic chemists

• Every unlabeled vertex is a C, and H attached to Cs (mostly) are not drawn

Heteroatoms

different atoms other than C and H

Carbocation

a molecule containing a + charged C atom with 3 bonds

Carbanion

C with a - FC, 3 bonds and a LP

Functional groups

a characteristic group of atom/bonds that possess a predictable chemical behavior

Alcane

hydrocarbon without π bonds

Alkene

hydrocarbon that has at least 1 C=C

Alkyne

hydrocarbon that has at least 1 C≡C

Alkyl halide

sp³ hybridized C, one of those bonds is to a halogen

Acyl halide

alkyl halide with a =O bonded to the C that’s bonded to the halogen

Alcohol

OH bonded to a C chain

-Most famous alcohol: drinking alcohol

-Categorized based off the C they’re attached to

Carboxylic acid

alcohol w/ =O added directly adjacent to the OH

-More acidic than alcohol

Ether

O with 2 C chains

Diethyl ether

most famous ether

Ester

ether with =O added directly adjacent to the non-double-bonded O

-Undergo more RXNs than ethers

Amine

Compounds containing a N connected to 1-3 alkyl are aryl groups

-Categorized by how many C the N is bonded to

-Can be 4° as ions in rare cases

Amide

amine with a =O directly adjacent to the N

Carbonyl group

C=O

-Not a functional group

Aldehyde

carbonyl group bonded to a H atom and 1 C chain

Ketone

carbonyl group bonded to 2 C chains

Aromatic

-

Benzene

the most common aromatic compound

Benzene ring

a structure of 6 C atoms that are each bonded to a H atom

(ex of a benzene ring)

Shows delocalization of π e- in the ring

Halo compound

any compound containing a halogen atom

Resonance

implies delocalized π e-s

Resonance hybrid

the real molecule

-π bond shared to multiple locations

Drawing resonance structures

1. non-bonding e-s can move to an adjacent bond

2. π e-s can move to an adjacent atoms or adjacent bond

3. e-s can’t move toward an sp³ hybridized atom (the octet rule would be violated)

Double headed arrow

shows the movement of 2 e- at a time

Single headed arrow

show the movement of 1 e- at a time

Allylic

1 bond away from an alkene

-If on 1 of the allylic Cs it has a +FC, LP, or radical

→it will have resonance

Benzylic

1 bond away from a benzene ring

-If the benzylic C has a +FC, LP, or radical

→It will have resonance

Radical

Homolytic cleavage

when 2 e- and a bond move in opposite directions

Major

the resonance hybrid looks more like them

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