How can I determine bond polarity?
You'll need to take the difference between the electronegativity value of the two atom. Their bond polarity is determined according to the range it falls in:
- Nonpolar covalent: Electronegativity difference < 0.5
- Polar covalent: Electronegativity difference is 0.5 - 1.6
- Ionic: Electronegativity difference >2
For electronegativity difference 1.7 - 2, it's
- polar covalent if both atoms are nonmetals
- Ionic if one of the atom is a metal
*the ranges may vary slightly depending on which source is used as reference; do check with your school.
Electronegativity values look like this
Let's take a look at some examples.
- HF - electronegativity difference = 4.0 - 2.1 = 1.9,
- CBr - electronegativity difference = 2.8 - 2.5 = 0.3
- LiF - electronegativity difference = 4.0 - 1.0 = 3.0