1. The Polarity of Covalent bonds

2. The Polarity of Covalent bonds
Two nonmetallic atoms will share their electron pairs unequally when they have different elect- ronegativities.
The atom with the higher electronegativity will have the electrons “more often” than the atom with the lower electronegativity.
But I get them more often!
We’ll
share.
My electrons!
My electrons! e- e-
EN = 2.6
EN = 3.5

3. The Polarity of Covalent bonds
When electrons are shared unequally, the bond is a polar covalent bond! H CI  δ+ δ–  H CI  H CI  
EN = 2.1
EN = 3.2
EN = 3.5 H O  H O  H O  δ+ δ–
EN = 2.1

4. The Polarity of Covalent bonds
The larger the ∆EN is, the more polar the bond will be.  H CI
∆EN = 1.1 
EN = 2.1
EN = 3.2
The covalent bonding in H2O is more polar than the covalent bonding in HCl.
EN = 3.5 H O 
∆EN = 1.4
EN = 2.1

5. The Polarity of Covalent bonds
Two nonmetallic atoms will share their electrons equally when they have the same electronega-tivities.
When electrons are shared equally, the bond is a nonpolar covalent bond.
Our EN’s are the same!
We’ll share 50 – 50! e- e-
EN = 2.1
EN = 2.1

6. The Polarity of Covalent bonds
The diatomic free elements exhibit nonpolar covalent bonding between the atoms.
A sample of most other pure nonmetals exhibit nonpolar covalent bonding between the atoms.  F  O H N   Br I   Cl
C(s)
S(s)
P(s)
Si(s)

7. The Polarity of Covalent bonds
Ex. (1) If element M (EN = 0.4) and element X (EN = 3.1) bond, the bonding would most likely be classified as
(1) ionic (3) polar covalent
(2) metallic (4) nonpolar covalent
Ex. (2) Which of the following formulas contains covalent bonding with the greatest degree of polarity?
(1) HF (3) HBr
(2) HCl (4) HI

8. The Polarity of Covalent bonds
Ex. (3) What type of bonding is characterized by an equal sharing of electrons?
(1) ionic (3) polar covalent
(2) metallic (4) nonpolar covalent
Ex. (4) Which of the following formulas contains bonding that is characterized by an unequal sharing of electrons?
(1) H2O (3) NaCl
(2) Ag (4) N2

9. The Polarity of Covalent bonds
Ex. (5) If element D (EN = 2.6) and element Z (EN = 3.5) bond, the bonding would most likely be classified as
(1) ionic (3) polar covalent
(2) metallic (4) nonpolar covalent
Ex. (6) What type of bonding is characterized by a mobile sea of electrons?

10. The Polarity of Covalent bonds
Ex. (7) The bonding between the atoms in oxygen gas is
(1) ionic (3) polar covalent
(2) metallic (4) nonpolar covalent
Ex. (8) What type of bonding is characterized as having the greatest degree of polarity?

11. The Polarity of Covalent bonds
Ex. (9) What type of bonding is characterized as having an electronegativity difference equal to zero?
(1) ionic (3) polar covalent
(2) metallic (4) nonpolar covalent