1. Polarity

2. What is polarity?
Polarity is an unequal charge distribution across a covalent bond.
Some covalent bonds act like one atom is slightly negative and the other atom is slightly positive.

3. What causes polarity?
In many covalent bonds, one of the atoms has a higher electronegativity than the other.
The atom with the higher electronegativity keeps the electron longer than the other atom.
This gives it a slightly negative charge.

4. How do we determine if a bond is polar?
Subtract the electronegativities.
If the difference is equal to or greater than 1.8, it is ionic
If the difference is between 1.7 and 0.6, it is polar covalent
If the difference is 0.5 or less, it is nonpolar covalent.

5. Practice Problem w/ Drawing
Determine the polarity of a C-H bond.

6. Practice Problem 2
Determine the polarity of a Se-F bond.

7. Diatomic elements
Seven elements are generally found in paired atoms in nature.
H2, O2, F2, Br2, I2, N2 Cl2
Memory trick: Dr. HOFBrINCl always delivers twins.
Diatomic elements are always nonpolar.