1. Aim: How Can I identify a polar molecule from a non-polar molecule ?? ***
Do-Now: What type of bond do the following compound have
Use electronegativity differences between the elements as your reasoning.
What type of bond does….. F2 CF
CH3
HCl

2. How to show a bond is polar
Isn’t a whole charge just a partial charge
d+ means a partially positive (less electronegative)
d- means a partially negative (more electronegative)
The Cl pulls harder on the electrons
The electrons spend more time near the Cl d+ d- H Cl

3. Polar Molecules Molecules with a positive and a negative end
Requires two things to be true
The molecule must contain polar bonds
This can be determined from differences in electronegativity.
Asymmetric molecule.

5. Symmetrical Molecules
Because of symmetry, molecules that have polar bonds are overall a nonpolar molecules (+ and – charges cancel out or balance out)
Examples:
CO BF3
CCl4

6. Asymmetrical Molecules
If a molecule has polar bonds (and there is no symmetry to cancel out + and – charges), the molecule is polar.
Examples:
H2O HCl
NH3

7. Check for Understanding # 1
*****
Everyone Writes: List 5 differences between polar and non-polar molecules in your notebook. ( 3 minutes)

8. Dipole When there is unequal sharing of electrons a dipole exists
Dipole is a molecule that has two poles or regions with opposite charges
A dipole is represented by a dipole arrow pointing towards the more negative end

9. Dipole
**Turn+ Talk= Take 1 minute to turn and talk to your elbow partner,
Based on the image, what kind of molecules will Co2 and H20 be, make sure to use reasoning
to explain your answer.

11. Do-now: Practice Drawing Dipoles
Aim: How Can We Practice Writing Dipole Moments and
identify polar and non-polar molecules?
Do-now: Practice Drawing Dipoles
HW: Practice Test Online due 12/5/16
P- Br P = 2.1 Br = 2.8
P –Br
 -
Remember to write down positive
Atom first, the one with the lower
Electronegativity is the positive one!
Practice
H(2.1) – S(2.5)
F(4.0) - C(2.5)
C(2.5) - Si(1.8)
N(3.0) – O(3.5)

12. H –S
 -
C-F
 -
SI –C
 -
N–O
 -

13. Is it a Polar or non-Polar molecule?HF
H2O
NH3
CF4
CO2
Polar molecule
Polar Molecule

14. Answers

15. CF4
Non-Polar Molecule

16. Non Polar Molecule

17. Summary
In a polar bond, one atom is more electronegative than the other.
In a nonpolar bond, both atoms have similar electronegativities.
An asymmetric molecule with polar bonds is a polar molecule.
An asymmetric molecule with nonpolar bonds is a nonpolar molecule.
A symmetric molecule, regardless of the polarity of the bonds, is always a nonpolar molecule.