1. Lecture 8A - Formation of Covalent (Molecular) Compounds

2.  This is called a Structural Formula
I. Covalent Bonds
A. These bonds are formed from two atoms _________ electrons, so each atom will have a filled outer energy level.
sharing
1 dash represents 2 electrons
A bond is drawn as a dash:
 This is called a Structural Formula
B. Three types of bonds can be formed:
1 pair of electrons are shared between 2 atoms, 2e- total
Single -
2 pairs of electrons are shared between 2 atoms, 4e- total
Double -
3 pairs of electrons are shared between 2 atoms, 6e- total
Triple -

3. Cl Cl H H II. Bond Formation
A. Covalent bonds are formed from two or more ______________ ONLY, which are found in groups:
nonmetals
4A-7A
The sharing of e- will allow each atom to achieve a stable noble gas e- configuration.
Each atom will have 8 valence electrons or a full octet creating filled orbitals.
As the shared e- moves back & forth between the ½ filled orbitals in the atoms, there is a split moment when both e- shared will be in the same orbital creating a filled orbital, & a noble gas configuration is achieved.
Exception: Cl Cl H H
Stable configuration
Circle the shared electrons

4. III. Review Ionic Compounds vs. Covalent Compounds Ionic Bonds
Covalent Bonds
Anion & cation
2 or more nonmetals
Transfer e-: Arrow is used
Share e-: Draw a line to show shared e- between the 2 atoms
Chemical Formula = Formula Unit
Chemical Formula = Molecular formula
A line is not used to represent a bond, why?
A line is used to represent a bond, why?
Share e-
Don’t share e-

5. Three pairs of electrons
Covalent Bonds
two atoms share e-
One pair of electrons
Two pairs of electrons
Three pairs of electrons
called
called
called
Single bond
Double bond
Triple bond
Drawing covalent molecules takes practice & patience! Practice makes perfect!