Orgo chem 1 exam 1

Organic chemistry

Study of carbon cintaining compounds

What are compounds made of

Elements

What are elements made of

Atoms

Proton charge

Positive

Neutron charge

Neutral

Electron charge

Nergative

Where is most of the mass of an atom

Nucleus

Where's most of the volume of an atom

Electron cloud

What is Z

Atomic number

What is the atomic number (Z)

Number of protons

H²

Deuterium

Top right of an element is the

Mass number (A)

Bottom right of an element is

Atomic number

What is the mass number

Sum of protons and neutrons

Isotopes

Elements that have the same number if protons but have a different number of neutrons

Atomic mass (amu)

Weighted average of the element's naturally occuring isotopes

Where are valence electrons located in the atom

Outermost shell

What is involved in forming bonds

Valence electrons

Octet rule

The tendency of an atom to achieve a configuration where its valence shell has 8 electrons (elements after Si is the exception)

Which elements only form one bond

H, F, Cl, Br, I

Which element forms two bonds

O

Which element forms three bonds

N

Which element forms four bonds

C

Isomers

Different compounds that have the same molecular formula but different physical properties

Constitutional isomers

Different compoundd that have the same molecular formular but differ in the connectivity of their atoms

Effects of H bonding

Increased boiling point and melting point

Ionic bonds

Formed from transfer of electrons, is an attractive force between oppositely charged jobs, comes from atoms with large electronegativity differences

Covalent bonding

Bonds formed from sharing electrons

Which atom usually makes covalent bonds

C

What's the most electronegative element

Fluorine (F)

What's the least electronegative element

Fracium (Fr) or Cesium (Cs)

Tetravalent

Always forms 4 bonds when joined to other elements (C)

Tetrahedal compounds

represented with dashes (back) and wedges (front), has two on the plane, two out

Formal Charge Equation

FC = VE - dots - lines

What is X

Halogens: F, Cl, Br, I

Rules for Resonance Structures

1. Identify mobile e- → lone pairs and pie bonds

2. Curved arrow to show movement of e-

3. Only move e-, not atoms

4. Most atoms cannot have more than 8 e-

5. Avoid breaking sigma bonds

6. Prioritize Stability

• Minimize FC

• EN atoms prefer (-) charges

• Avoid carbocations

7. Charge is maintained in resonance structure

Delocalized

Where e- is spread across a system

Resonance stabilization

The energy of the actual molecule is lower than the energy of any resonance structure (spreads charge across the molecule)

What effects stability

More covalent bonds = more stable, charge seperation decreases stability, full octet = most stable, negative charge on high EN atom is more stable than a negative charge on a less EN atom

Orbital

Region of space with the greatest probability of finding an electron

Shell

Orbital arranged in layers around the nucleus

Aufbau Principle

Lowest energy orbitals are filled first

Pauli exclusion Principle

Maximum.of 2 electrons in each orbital and must have paired spins (one up one down)

Hund's Rule

Add one electron to each orbital with spins unpaired until each orbital of the same energy contains one electron then fill in the 2nd electron

Electron configuration of Li

1s²2s¹

^ | ^

| v |

Heidelberg uncertainty principle

We cannot simultaneously know the position and momentum if an electron

Linear Combination of Atomic Orbitals (LCAO)

Orbitals can combine which leads to bonding

orbital on different atoms can produce molecular orbital

Orbital on the same atom can combine to form hybridization atomic orbitals

Bonding MO

Results when the same phase orbitals overlap

Antibodies MO

Results when the opposite phase orbitals overlap

Number of MOs that results is always equal to

The number of AOs (two atomic orbitals = two molecular orbitals

Hybridization

When the mixing of atomic orbitals can form hybrid orbitals (s + 3p =sp³)

VSEPR

atoms must be as far apart as possible

How to determine hybridization

Count the number of atoms and lone pairs attached to the atom

ex.

H-O-H

2 lone pairs + 2 pairs so sp³

Cis isomer

Largest atomic number on the SAME side of double bond. If you line the two bonds up with their directions with a pencil, if they cross then its cis

Polar

Trans isomer

Largest atomic number on the OPPOSITE side of the double bond. If you line the two bonds up with their directions with a pencil, if they're parallel then its trans

Nonpolar

The more S character then

The shorter the bond

Lewis dot formula

Dots represent bonds and lone pairs

Dash formula

Bonds are shown as dashes

Condensed formula

Condenses the formula into structural segments

Bond-line or skeletal formula

Lines represent bonds; typically carbond and hydrogens are not shown unless part of the functional group

Three-dimensional formula

Shows the 3-D nature of the molecule by using dashes and wedges

Alkane

Hydrocarbon with only single bonds

ex.

propane

CH3CH2CH3

/\

Ending in ane

Alkene

Contains a carbon-carbon double bond

ex.

Ethene

H2C=CH2

=

Ending in ene

Alkyne

Contains a carbon-carbon triple bond

ex.

Ethyne

HC≡CH

≡

Ending in yne

Arene

Six membered ring with alternating double or single bonds

ex.

/\

| |

\/

Each carbone is sp²

Ending in ene

Phenyl group

Benzene ring attached to another group

Benzyl group

Phenyl - methylene (-CH2-)

Polar covalent bonds

Formed from atoms with different EN

Has a dipole

Prefix for 1 carbon

Meth-

Prefix for 2 carbons

Eth-

Prefix for 3 carbons

Prop-

Prefix for 4 carbons

But-

Prefix for 5 carbons

Pent-

Prefix for 6 carbons

Hex-

Prefix for 7 carbons

Hept-

Prefix for 8 carbons

Oct-

Prefix for 9 carbons

Non-

Prefix for 10 carbons

Dec-

Alkane for 1 carbon

Methane

Alkene for 2 carbons

Ethane

Alkene for 3 carbons

Propane

Alkane for 4 carbons

Butane

Alkane for 5 carbons

Pentane

Alkane for 6 carbons

Hexane

Alkane for 7 carbons

Heptane

Alkane for 8 carbons

Octane

Alkane for 9 carbons

Nonane

Alkane for 10 carbons

Decane

Alkyl group for 1 carbon

Methyl

Alkyl group for 2 carbons

Ethyl

Alkyl group for 3 carbons

Propyl

Alkyl group for 4 carbons

Butyl

Alkyl group for 5 carbons

Pentyl

Alkyl group for 6 carbons

Hexyl

Alkyl group for 7 carbons

Heptyl

Alkyl group for 8 carbons

Octyl

Alkyl group for 9 carbons

Nonyl

Alkyl group for 10 carbons

Decyl

Abbreviation for Methyl

Me

Abbreviation for ethyl

Et