CHEM 2211 Exam 1 UGA

Electronegativity trend

increases up and to the right

Ionic bond electronegativity difference

greater than 1.9

Covalent bond electronegativity difference

less than 0.5

Polar covalent bond electronegativity difference

between 0.5 and 1.9

types of covalent bond breakage

homolytic cleavage and heterolytic cleavage

Homolytic cleavage

non-polar covalent bond breaks, each atom keeps one electron(radicals)

Heterolytic cleavage

polar covalent bond breaks, more electronegative atom keeps both electrons (anion)

Nitrogen preferred bonding

3 bonds

1 lone pair

Oxygen preferred bonding

2 bonds

2 lone pairs

Carbon preferred bonding

4 bonds

0 lone pairs

Halogen preferred bonding

1 bond

3 lone pairs

Formal Charge=

# Valence electrons - (# dots + # lines)

Kekule structures

lewis structure without lone pairs

constitutional isomers

have same molecular formula but different connectivity

they will have different physical properties

Condensed formula

organic compounds read then written from left to right in sequential order

how are substituents notated in condensed formulas

in parenthesis after hydrogens

what is the space in between shaded regions called on a p orbital

node

Aufbau Principle

lower orbitals most be filled first

Pauli Exclusion Principle

each orbital can have 2 electrons, they must have opposite spins

Hund's Rule

orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin

molecular orbital theory

when two atomic orbitals combine, two molecular orbitals are produced, a bonding and anti-bonding molecular orbital

The bonding MO is spin-paired and the anti-bonding MO is not

HOMO

highest occupied molecular orbital

LUMO

lowest unoccupied molecular orbital

Sigma bonding

when orbitals overlap head on with the same shading

Sigma anti-bonding

form when valent orbitals overlap head on and out of phase (opposite shading)

Pi bonding

side-to-side overlap that results in double or triple bonds

P orbitals overlap vertically with the same shading

Pi anti-bonding

P orbitals overlap vertically and out of phase (opposite shading)

sp3 hybridization

tetrahedral

109.5 degrees

sp2 hybridization

trigonal planar

120 degrees

sp hybridization

linear

180 degrees

electronic geometry vs molecular

electronic is without counting lone pairs, molecular takes lone pairs into account

sp3 molecular geometry

tetrahedral

trigonal pyramidal

bent

sp2 molecular geometry

trigonal planar

bent

% s character =

s orbitals / (s orbitals+ p orbitals) x 100

the bigger the halogen, the _________ the bond is to the hydrogen. The bigger the bond, the _________ it is

longer

weaker

allylic resonance

when a cation, anion, lone pair, or radical is located adjacent to a bond

lone pair resonance

lone pair on an atom, N or O, shares a lone pair with an adjacent electron deficient, positively charged, atom

rules of resonance

1. Net charge MUST remain constant

2. NEVER break sigma-bonds when trying to create new resonance structures, only pi-bonds can move

3. Do not violate the octet rule

Alkane

alkyl halide

Alkene

Alkyne

Arene

Alcohol

Ether

Epoxide

Thiol

Thioether

Amine

Amine 2*, Amine 3*

Aldehyde

Ketone

Carboxylic acid

Ester

Acyl halide

Anhydride

Amide

Nitrile

What are 11 and 12 hydrocarbon chains called

Undecane

Dodecane

Primary Carbon

a carbon bonded to only one other carbon

Secondary Carbon

carbon bonded to two other carbons

Tertiary Carbon

carbon bonded to three other carbons

Quaternary Carbon

carbon bonded to four other carbons

Primary alcohol

an alcohol in which the hydroxyl (-OH) group is attached to a carbon that is attached to no more than one other carbon.

Secondary alcohol

An alcohol in which the hydroxyl (-OH) group is attached a carbon that is attached to two other carbons.

Tertiary alcohol

An alcohol in which the hydroxyl (-OH) group is attached to a carbon that is in turn attached to three other carbons.

Primary amine

Nitrogen has one or zero carbons attached to it

Secondary amine

nitrogen has two carbons attached to it

Tertiary amine

nitrogen has three carbons attached to it

Quaternary amine

nitrogen has four carbons attached to it

IUPAC name breakdown

Sub, Par, Sat, PG

isopropyl

Tert-butyl

sec-butyl

isobutyl

double bond saturation

_____ - # - ene

triple bond saturation

_____ - # - yne

who is given priority in the direction of the parent chain

priority groups, OH

pi bonds if not OH

If alkene and alkyne are tied in position on the parent chain

prioritize the alkene

vinyl

allyl

What is an alkene substituent directly attached to a parent chain called?

alkyl-idene

exception, methylene

Common names for simple molecules

Alkyl Halide

Alkyl Ether

Alkyl Alcohol

Alkylamine

Methyl Group

CH3

Methylene Group

CH2

Methine Group

CH

like dissolves like

polar dissolves polar, nonpolar dissolves nonpolar

Anti-staggered conformation

the two largest groups are 180° apart, and strain is minimized

gauche interactions

when nonhydrogen atoms are next to each other in a staggered projection

conformational isomers

compounds that share the same molecular formula and connectivity due to single-bond rotation

eclipsed interactions

strain caused by overlapping molecules in eclipsed formations

which formation has the highest energy

eclipsed with the largest atoms overlapping

What does an eclipsed line bond look like

What does a sawhorse projection look like

steric strain

repulsion of neighboring electron clouds of substituents

examples of steric strain

gauche interactions

also occurs in eclipse interactions

torsional strain

arises from stored potential energy within bonds and unfavorable orbital overlap

examples of torsional strain

eclipse interactions

when bonds form how does energy change

energy is released

which type of cleavage is more common?

heterolytic