Sunday, May 22, 2011

chemical bonding (by: mandy)

                                                         CHEMICAL BONDING
There are 3 types of chemical bondings: Ionic Bonding, Nonpolor Covalent Bonding, and Polar Covalent Bonding.
Nonpolor Covalent Bonding: electrons are shared equally
Polar Covalent Bonding: electrons are shared unequally
Ionic Bonding: electrons are transferred between two atoms

Electrostatic Force
Electronegativity: the measure of the ability of an atom to attract electron from other atoms.
Metals have LOW electronegativity
Non-metals have HIGH electronegativity
*The greater the difference of electronegativity, it is more likely to be Ionic Bond
           ENeg Diff. = | ENeg1- ENeg2 |

ENeg Diff. <0.5 (non-polar covalent)
ENeg Diff. 0.5 to 1.8 (polar covalent)
ENeg Diff. >1.8 (ionic)

London Forces

Polar Covalent Bonds

A molecule is polar if there is an imbalance with electrical charge. [This is called: Polarity]

Atoms with higher electronegativity (delta -)
Atoms with lower electronegativity (delta +)

For example:

Hydrogen has an electronegativity of 2.1
Oxygen has an electronegativity of 3.5
therefore, O, with the higher electronegativity is labelled delta- and two H are labelled delta+

Arrow should be pointing at the negative atom.

study hard!

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