Chemical Bonding & Isomers Pages

Recall the petroleum refining…. What is this next slide a diagram of?

What are intermolecular forces?

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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

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 CH 4 Carbon has 4 valence e - 4 H each have 1 valence e -

Structural formulas  A 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 C 8 H 18

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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.