Chemical bonds form as atoms seek stability by filling their outer electron shells. Atoms can gain or lose electrons to form ions, or share electrons in covalent bonds. Covalent bonds occur when atoms share valence electrons to fill their octets. A single bond shares one pair of electrons, a double bond shares two pairs, and a triple bond shares three pairs. Lewis dot structures use dots to represent valence electrons and show how atoms bond to fill their octets. Molecules like methane, oxygen, nitrogen, water, carbon dioxide, and carbon monoxide can be represented using Lewis dot structures.

1. Bonding
How are chemical bonds formed?

2. Chemical Bonds
• Atoms are most stable _______________
_________________________________
• To obtain a full shell atoms can:
–______________or __________ electrons
(forming cations or anions)
–___________ electrons (form a covalent
bond)

3. Covalent Bonds
• Non-metals generally have 4,5,6,7 or 8 electrons in
the outer shell
• If they bond with each other, electrons are shared
Cl Cl
valence electrons can be shared
Cl Cl
Outer shells overlap and
valence electrons are shared

4. Bonds
• Covalent bonds
– _________________________________________
_________________________________________
– Valence electrons are shared between
___________ atoms to fill a an atom’s octet
• ___ shared electrons: single bond
• ___shared electrons: double bond
• ___shared electrons: triple bond

5. Lewis Dot Structures –
Representing Elements
• Identify the number
of valence electrons
in each atom.
• Spread them around
the atom symbol –
first individually,
then in pairs
• Oxygen= _________
O

6. Lewis Dot structures of molecules
• Method #1
– Put your atoms together.
– If Octet is not filled, slide e-
pairs to form double, triple
bonds.
• Method #2
– Count total number of
valence electrons.
– Fill central atom’s octet
first
– Create double, triple bonds
if necessary.

7. Covalent compounds
• Draw electronic structure diagrams to show
how the following elements or compounds
are formed:
– Methane (CH4)
– Oxygen (O2)
– Nitrogen (N2)
– Water (H2O)
– Carbon dioxide (CO2)
– Carbon monoxide (CO)

8. Naming Covalent Compounds
• Draw the structure to find out how many of
each element there are.
• Write the formula with correct subscripts.
• Name the formula- write the names of the
elements.
• Include prefixes to match subscripts.
– NO MONO- on the first element!
• Make sure there’s an “-ide” on the end.

9. Prefixes
• 1- Mono-
• 2- Di-
• 3-
• 4-
• 5-
• 6-
• 7-

10. Covalent name formula
• To do this you….

11. Fill in the following table:
# EACH ATOM FORMULA NAME Bond types
1 CARBON, 4
CHLORINE
HS2
Sulfur dioxide
Sulfur trioxide
2Nitrogen
4Oxygen