Polar and Nonpolar Covalent
Bond
Polar Covalent Bond
• a type of chemical bond where a pair of electrons is unequally
shared between two atoms. In a polar covalent bond, the
electrons are not equally shared because one atom spends
more time with the electrons than the other atom.
• In polar covalent bonds, one atom has a stronger pull than the other
atom and attracts electrons.
• Ex: H2O
Nonpolar Covalent Bonds
• a type of bond that occurs when two atoms share a pair of
electrons with each other.
• These shared electrons glue two or more atoms together to
form a molecule.
• Ex: H2
How to Predict Bonding Type Using Electronegativity
• Electronegativity is how strongly an atom will attract electrons
from another atom in a chemical bond.
• When atoms have a different electronegativity, then electrons
are unequally shared.
• If you have two atoms with the same strength, or the same
electronegativity, electrons are equally shared between the two
atoms.
Rules:
1. If the electronegativity difference (usually called ΔEN) is less
than 0.5, then the bond is nonpolar covalent.
2. If the ΔEN is between 0.5 and 1.6, the bond is considered
polar covalent
3. If the ΔEN is greater than 2.0, then the bond is ionic.
4. If the ΔEN is between 1.6 and 2.0 and if a metal is involved,
then the bond is considered ionic. If only nonmetals are
involved, the bond is considered polar covalent.
Values of electronegativities are found on the Periodic
Table
• Common elements with their Electronegativity
Examples:
• Sodium bromide (NaBr) Na= 0.9 Br= 2.8
Br-Na (2.8-0.9=1.9)
Follow the rule number 4, since it is between 1.6 and 2.0 and metal
is
involved (Na) therefore it is an ionic bond.
• Hydrogen fluoride (HF) H=2.1 F=4.0
F-H (4.0-2.1=1.9)
Follow the rule number 4, since it is between 1.6 and 2.0 and both
are nonmetals then it is polar covalent bond.
• Iodine (diatomic) I2
I=2.5 (2.5-2.5=0)
Rule number 1, electronegativity difference is less than 0.5, then the
bond is nonpolar covalent.
Answer this!
• Identify the bond of the following. You can put you answers on
Microsoft word, or you can do handwritten. Short Bond-paper.
Copy and answer. Show your solutions.
1. F2
6. HCl
2. NaCl
7. ICl
3. SBr
8. MgBr
4. O2
9. LiF
5. CCl
10. AlS