May 18 2011 - Electronegativity and Polarity

It's the long weekend and my parents are on my tail about not doing any work, so here I am!  So lets see...what did we learn this class,OMGWTFBBQ.  What is this this thing called electronegativity and polarity.

Electronegativity is a measure of attraction of an atom for electrons in a covalent bond.  When 2 different atoms are covalently bonded, they share electrons.  This type of bond is polar.  Polar bonds result in unequal sharing of electrons in bonds.

Bond types
The difference in electronegativities of 2 elements can be used to predict the natures of bonds.  Bonds are categorized into 3 classes:

1. nonpolar covalent - electrons are shared equally between two atoms
2. polar covalent - one atom has a greater attraction for electrons than the other atom
3. ionic - bonding electrons are given away completely to one of the bonding atoms

Predicting Bond Types
When differences are less than 0.5, bonds are considered nonpolar.  (0-.04)
When differences are less than 1.7 and greater than 0.5, the bond is covalent.  (0.5-1.7)
When differences are 1.7 or greater, the bond is ionic
(1..7 and up)
*wait waaah?? shouldnt it be 1.8? N O.  I looked and I kept seeing 1.7 so get over it. *




Eg.
What type of bond will HCL be?
H has an electronegativity value of 2.10
CL has an electronegativity value of 3.16

Difference is: 3.16-2.10 = 1.06

ANSWER: Polar covalent bond  <------


hehe time for a hard one!!!!!
What type of bond will HF be?
H has an electronegativity value of 2.1
F has an electronegativity value of 4.0

Difference is: 4.0-2.1 = 1.9

ANSWER: get ready for this because whatever you got is wrong.  Its a POLAR COVALENT BOND.


Say whaaa???  How is it polar covalent.  Its an exception DEAL WITH IT.


This guy man, hes crazy but hes good.  Enjoy ^_^