Chemical Bonding & Isomers

Pages 181 - 191

Recall the petroleum refining….

What is this next slide a diagram of?

What are intermolecular forces?

Page 181

The larger the hydrocarbon molecules, the _______________, the intermolecular force.

The larger the hydrocarbon molecules, the STRONGER the intermolecular force.

The larger the hydrocarbon molecules, the _______________, the boiling point.

The larger the hydrocarbon molecules, the HIGHER the boiling point.

Do you remember why atoms are attracted to other atoms?

How many valence electrons does a C atom have?

Ions and Ionic bonding

From pages 32 - 34

Find Mg on the Periodic Table…

If an atom of Mg became an ion, How does its electron structure

change?What would be its charge?What would it be classified as?

If an atom of F became an ion, How its electron structure change?What would be its charge?What would it be classified as?

Chemical Bonding

Organic chemistry – study of hydrocarbons and their derivatives

Hydrocarbons – composed of carbon chains (backbone) with H atoms attached to remaining bonding sites

Chemical Bonding Electron-dot formulas

Each dot represents 1 valence e-

Dots placed between chem symbols represent electrons shared by atoms

Single covalent bond – a pair of electrons are shared between two atoms

Ex) methane CH4

Carbon has 4 valence e-

4 H each have 1 valence e-

Structural formulasA line can be used to represent a pair of

shared e- Remember – molecules are not

2-dimensional

Alkanes Alkanes - Simple hydrocarbon family

Each C forms single covalent bonds w/ 4 other atoms

Because each C atom is bonded to the maximum # of other atoms, it is said to be saturated

Alkanes

Straight-chain alkane – each C is linked to only 1 or 2 other C atoms

Straight-chain Alkanes

Alkanes

Branched-chain alkane – 1 or more C are linked to 3 or 4 other C atoms

Isomers - molecules with identical chemical formulas but different structural formulas

Ex) octane

C8H18

Page 187

Page 187

Isomers and Boiling Point

Q. Which isomer would have the lowest boiling point temperature?

Isomers and Boiling Point

A. The molecule on the right… branched shaped decreases surface area

which results in weaker intermolecular forces. This makes it easier for the molecules to evaporate.