1. Opener Recall: what is Electronegativity? Where can you find it?
What is the electronegativity of O? What do you know about the bonds oxygen molecules make in O2(g) ?
What are the electronegativities of H and Cl?
Based on what you now know about bonding, what do you anticipate might happen with HCl?

2. Polar Covalent Bonds

3. Covalent Bonds
Remember, Covalent bonds form between two atoms with high ionization energy and high electronegativity
The two atoms share the electrons between the nuclei

5. Water Water has two polar covalent bonds
The oxygen atom has a higher electronegativity than the hydrogen, so pulls the shared electron towards itself more than the hydrogen

6. Polar Covalent Bonds Since the electron spends more time around the
Cl nucleus,the Cl gains a partial negative charge,
and the H gains a partial positive charge
This is indicated in each diagram using the δ

8. Determining Polarity
We use electronegativity of each element to determine if a bond is polar
It is the difference in electronegativity that is important
Check : what is the difference in electronegativity of
H-F C-H P-Cl

9. Bond Continuum
An ionic bond is just an extreme polar covalent bond where the electron has been transferred from one atom to another
Difference in electronegativty
0.4
1.8
Pure
Covalent
Polar Covalent
Ionic

11. Determine Polarity
What type of bond forms between C and O? Li and Cl? Li and Se? P and N?

19. Now try
Draw structural diagrams for each molecule and indicate polarity where appropriate HBr Cl2

20. CH4 CH3OH