Organic Chemistry Exam #1

def of organic chem

chemistry of carbon compounds

structural theory

structure determines the properties

Ionic compounds

made from metal + non metal and the give up/take electrons

( metal always gives up e-)

Covalent Bonds

sharing electrons

Lewis structures!!

How many bonds do carbon, nitrogen, oxygen, hydrogen, fluorine, neon, and boron like to form

C- 4 bonds 0 LP

N- 3 bonds 1 LP

O- 2 bonds 2 LP

H- 1 bond 0 LP

Ne- 0 bonds 4 LP

B- 3 bonds 0 LP

Formal Charge Formula

valence electrons - bonds- # of lone pairs

Onium

1 extra bond and 1 less lone pair, leads to a +1 charge

Ide, Ate, or ite

one less bond and one extra lone pair, leads to -1 charge

Nitrogen, Oxygen, and Fluorine with +1 charge

N- Ammonia

O- oxonium

F- fluoronium

Carbon, nitrogen, oxygen, fluorine, and hydrogen with -1 charge

C- Carbanion

N- nitride

O- oxide

F- Fluoride

H- hydride

When do expanded octets occur

period 3 and below CAN have expanded octets and it relates to their column number

• More bonds= more stable

• always strive for minimized formal charge

alkane

carbon with 4 single bonds

alkene

carbon with 2 single bonds and one double bond

Allene

carbon with 2 double bonds

alkyne

carbon with 1 single bond and 1 triple bond

carbocation

carbon with 3 single bonds and a +1 FC

radical

carbon with 3 single bonds and 1 electron (not a lone pair)

• very unstable

• FC is 0

carbanion

carbon with 3 bonds and 1 lone pair with a -1 FC

Carbene

carbon with 2 bonds and 1 lone pair

• not stable

• FC of 0

Resonance

two structures with NO atoms moved around BUT the electrons move around

Resonance Theory/ Rules

1. the actual structure is a hybrid of all of the resonance structures

2. better resonance structures contribute more and equal structures contribute equally.

3. the hybrid is more stable than the contributing structures and we call that resonance stabilized

4. all atoms have to maintain their position

How to Evaluate Resonance Contributors

1. structures with complete valence shells are more important

2. structures with more bonds are important

3. structures with charged atoms are LESS important

4. More electronegative atoms hold electrons better

Isomers

different arrangement of atoms but has the same formula

Hydrocarbons

alkanes- C, H single bonds

Alkenes - C double bonded to C

Alkynes -C triple bond C

Aromatics - hexagon ring (benzene ring)

Functional Groups: Only Single Bonds

alcohols

ethers

alkyl halides

thiols

amines

Alcohols

C-O-H

Ethers

C-O-C

Alkyl Halides

C with 4 halogen bonds

Thiols

C with an SH group attached

Amines

C with a N attached

Carbonyl Compounds

ALL HAVE C doubled bonded to O

ketones

aldehydes

carboxylic acid

esters

amides

Ketones

C with 2 single bonded C’s and a double bond O

Aldehydes

C with a single bond C, single bond H, and double bond O

Carboxylic Acid

C single bond c, single bond OH, and double bond O

Esters

C single bond c, single bond O to single bond H, double bond O

Amides

C single bond C, single bond NH2, double bond O

Alkanes Numbers

1- methane

2- ethane

3-propane

4-butane

5-pentane

6-hexane

7-heptane

8-octane

9-nonane

10-decane

Linear Electron Geometry

Angle: 180

2 bonds, 0 lone pairs

Trigonal planar electron geometry

Angle: 120

• 3 bonds 0 LP = trigonal planar

• 2 bonds 1 LP = bent

Tetrahedral Electron Geometry

Bond: 109.5

• 4 bonds 0 LP = tetrahedral

• 3 bonds 1 LP = trigonal pyramidal

• 2 bonds 1 LP = bent

IUPAC naming general rules

• longest carbon chain

• number closest to first substituent

• list all in alphabetical order

• try to keep the numbers low

isopropyl

looks like a Y

n-butyl

normal 4 carbon chain

sec-butyl

attached on second carbon of n-butyl, also known as (1-methylpropyl)

isobutyl

looks like an ethyl with a V and is also know as (2-methylpropyl)

tert-butyl

looks like a turkey foot and it also known as 1,1-dimethylethyl

cis

same side/direction

trans

opposite sides or direction

Hybridization

area of overlap is the area on constructive interference or the most probable region

linear hybridization

2 bonds= sp

trigonal planar hybridization

3 bonds= sp2

tetrahedral hybridization

4 bonds= sp3

cis isomer hybridization

on either top or bottom, doubled bonded in the middle and the double bond cannot more because moving would break the pi bond

trans isomer hybridization

opposite top/bottom and left/right, doubled bonded in the middle and the double bond cannot more because moving would break the pi bond

reactivity of alkenes

pi bond breaks, sigma bond is stronger than the pi bond so during the addition reaction the pi bond is broken

equatorial or axial stronger?

equatorial is ALWAYS more stable