Intro to Bonding:
Part 2:
Covalent Compounds
(Type 3 Binary Compounds)
Types of bonds
• There are 3 types of bonds that we are going
to focus on:
1. Ionic Bonds
2. Covalent Bonds
• Polar
• Nonpolar
3. Metallic Bonds
Covalent Bonds
• A bonding force resulting from the sharing of
valence electrons.
• Covalent compounds result when a nonmetal
reacts with another nonmetal.
• This type of bond is not as strong as an ionic
bond.
Covalent Bonds
• Example:
– Water (H2O)
• There is no cation or anion
• Both Hydrogen & Oxygen are nonmetals
• Hydrogen has 1 valence electron
– Hydrogen needs 2 valence electrons to fill it’s outermost energy level
– Oxygen will share one of it’s electrons so that Hydrogen can fulfill the
duet rule (2 electrons in the outermost energy level).
• Oxygen has 6 valence electron
– Oxygen needs 8 valence electrons to fill it’s outermost energy level
– Each hydrogen will share it’s one electron so that oxygen can fulfill the
octet rule (8 electrons in the outermost energy level).
• If both hydrogen’s share their 1 valence electron with oxygen, then
each hydrogen will have a total of 2 valence electrons (duet rule)
and oxygen will have a total of 8 valence electrons (octet rule).
Single, Double, Triple Bonds
• By drawing the Lewis dot structure, you can
determine if there is a single, double, or triple
bond between atoms.
• Single bond
– Each atom shares one valence electron
• Double bond
– Each atom shares two valence electrons
• Triple bond
– Each atom shares three valence electrons.
Single, Double, Triple Bonds
• Bonds are represented by solid lines:
Nonpolar Covalent Bonds
• A nonpolar covalent bond is when electrons
are shared equally.
• An example is Oxygen gas (O2):
– Each oxygen atom has 6 valence electrons
– Each oxygen is going to share 2 valence
electrons.
– Oxygen is left with 2 lone pairs on
each oxygen atom. Thus there is an
equal distribution of electrons.
– Oxygen gas would be a nonpolar
covalent compound.
Polar Covalent Bonds
• A polar covalent bond is when electrons are shared
unequally.
• An example is Water (H2O):
– Each hydrogen has 1 valence electron.
– Oxygen has 6 valence electrons.
– Each hydrogen will share it’s one electron so that
oxygen can fulfill the octet rule.
– Oxygen will share one of it’s electrons so that Hydrogen
can fulfill the duet rule.
– Hydrogen is left without any lone pairs.
Oxygen has 2 lone pairs. Thus there is an
unequal distribution of electrons.
– Water would be a polar covalent compound.