Key Point for Chapter 25

( General Chemistry II )

Ch 25 Organic Chemistry

Hydrocarbon: Molecule contains H and C atom Only.

Alkane Alkene Alkyne

Formula CnH2n+2 CnH2n CnH2n-2

Bond single double triple

Hybrid

Orbitals SP3 SP2 SP

# of Hybrid

orbitals 4 3 2

Bond Angle 109 120 180

Electron

Geometry tetrahedral trigonal planar linear

Saturation Saturated Unsaturated Unsaturated

2. Classification of Alkane

Primary --- one neighboring atom is C

Secondary ----- two ----------------atoms are C

Tertiary .... three -------------- atoms are C

Quaternary ---- four --------------- atoms are C

3. Pi Electrons ---

Electron in P orbitals ---

a) double bond

b) Sp2

c) three bonding sites ** ( ring exception )

d) trigonal planar geometry

ALKANE ( Aliphatic Alkane )

(1). Naming:

a. First ten Alkane ( CH4 --- C10H22 )

b. IUPAC

Meaning Decided by

Parent :: What molecule it is Longest, Continuos Chain

Prefix :: What functional it is CnH2n+1 ( Alkyl)

Suffix :: Position of the Fcn gp Lowest number along the chain

Rule: ( in the order of priority )

1. Parent must be in the longest chain

2. Alphabetical

3. Total suffix numbers as low as possible

Note: 1: Di. Tri, Tetra.... are not considered as Alphabetical

2. Iso (CH3)2CH----- and Neo (CH3)3C------ are alphabetical

3. Bending and Rotation does not change the identity.

4. You can not put methyl or higher on 1

You can not put ethyl or higher on 2

.............................................. ...........

5. Count the number of C to differentiate the Parent and the Fcn Gp.

( 2 ) CONSTITUTIONAL ISOMER

Molecules have the same molecular formula but with different structures

Rule to tell the constitutional isomer::

Constitutional isomers must have different names

( 3 ) CYCLOALKANES

NAMING

Alkene

Naming: 1. Longest Chain contains double bond

2. Two double bond :: use ---adiene

3. Cycloalkene :: double bond must between C1 and C2.

4. First substituent must be as low as possible

1,5-Dimethylcyclopentene ( not 2,3-Di...............)

Cis - Trans