1. Chapter 8
Covalent Bonding

2. Sharing is Caring
The atoms held together by sharing electrons are joined by a Covalent Bond.

3. 2. Covalent bonds- Two atoms share one or more pairs of outer-shell electrons.
Oxygen Atom
Oxygen Atom
Oxygen Molecule (O2)

4. Molecules and Molecular Compounds
Molecule is a neutral group of atoms joined together by covalent bonds.
Diatomic molecule is a molecule consisting of two atoms.
A compound composed of molecules is called a molecular compound.

5. Properties
Molecular compounds tend to have relatively lower melting and boiling points than ionic compounds.
Many are gases or liquids at room temperature.
Most are formed from atoms of two or more nonmetals.

6. Molecular Formulas
A molecular formula is the chemical formula of a molecular compound.
It shows how many atoms of each element a molecule contains.
CO2 Carbon Dioxide
1 Carbon Atom
2 Oxygen Atoms

7. Ionic Vs. Covalent Bond

8. So
what
are
covalent
bonds?

9. In covalent bonding,
atoms still want to achieve
a noble gas configuration
(the octet rule).

10. But rather than losing or gaining electrons,
In covalent bonding,
atoms still want to achieve
a noble gas configuration
(the octet rule).
But rather than losing or gaining
electrons,
atoms now share an electron pair.

11. The shared electron pair is called a bonding pair
In covalent bonding,
atoms still want to achieve
a noble gas configuration
(the octet rule).
But rather than losing or gaining
electrons,
atoms now share an electron pair.
The shared electron pair
is called a bonding pair

12. Chlorine
forms a
covalent
bond
with
itself
Cl2

13. How
will
two
chlorine
atoms
react? Cl Cl

14. Cl Cl Each chlorine atom wants to
gain one electron to achieve an octet

15. Cl Cl do to achieve an octet? What’s the solution – what can they
Neither atom will give up an electron –
chlorine is highly electronegative.
What’s the solution – what can they
do to achieve an octet?

16. Cl Cl do to achieve an octet? What’s the solution – what can they
Neither atom will give up an electron –
chlorine is highly electronegative.
What’s the solution – what can they
do to achieve an octet?

17. Cl Cl
octet

18. Cl Cl octet circle the electrons for each atom that completes
their octets

19. Cl Cl The octet is achieved by each atom sharing the
electron pair in the middle
circle the electrons for
each atom that completes
their octets

20. Cl Cl The octet is achieved by each atom sharing the
electron pair in the middle
circle the electrons for
each atom that completes
their octets

21. Cl Cl This is the bonding pair circle the electrons for
each atom that completes
their octets

22. Cl Cl It is a single bonding pair circle the electrons for
each atom that completes
their octets

23. Cl Cl It is called a SINGLE BOND circle the electrons for
each atom that completes
their octets

24. Single bonds are abbreviatedCl Cl
Single bonds are abbreviated
with a dash
circle the electrons for
each atom that completes
their octets

25. This is the chlorine molecule,Cl Cl
This is the chlorine molecule,
Cl2
circle the electrons for
each atom that completes
their octets

26. Naming Covalent Compounds
Covalent compounds are named by adding prefixes to the element names.
The compounds named in this way are binary covalent compounds.
‘Binary’ means that only two atom are present.
‘Covalent’ (in this context) means both elements are nonmetals.
A prefix is added to the name of the first element in the formula if more than one atom of it is present. (The less electronegative element is typically written first.)
A prefix is always added to the name of the second element in the formula. The second element will use the form of its name ending in ‘ide’.

27. Naming Covalent Compounds
Prefixes
Subscript
Prefix 1
mono- 2
di- 3
tri- 4
tetra- 5
penta-
Subscript
Prefix 6
hexa- 7
hepta- 8
octa- 9
nona- 10
deca-
Note: When a prefix ending in ‘o’ or ‘a’ is added to ‘oxide’, the final vowel in the prefix is dropped.

28. Naming Binary Covalent Compounds: Examples1
mono 2 di 3
tri 4
tetra 5
penta 6
hexa 7
heptaa 8
octa 9
nona 10
deca
* Second element in ‘ide’ from
* Drop –a & -o before ‘oxide’
N2S4
dinitrogen tetrasulfide
NI3
nitrogen triiodide
XeF6
xenon hexafluoride
CCl4
carbon tetrachloride
P2O5
diphosphorus pentoxide
SO3
sulfur trioxide

29. Classifying Compounds
Classifying a compound using its name is not as difficult as using its formula.
The names of covalent compounds will be easily recognized by the presence of the prefixes (mono-, di-, tri-, etc.).
If no prefixes are present in the name, the compound is ionic. (Exception: some polyatomic ion names always contain prefixes (such as dichromate) but those will be memorized and recognized as ions.)

30. Writing Formulas for Covalent Compounds
The names of covalent compounds contain prefixes that indicate the number of atoms of each element present.
If no prefix is present on the name of the first element, there is only one atom of that element in the formula (its subscript will be 1).
A prefix will always be present on the name of the second element. The second element will use the form of its name ending in
Remember:
The compounds named in this way are binary covalent compounds (they contain only two elements, both of which are nonmetals).
When in covalent compounds, atoms do not have charges. Subscripts are determined directly from the prefixes in the name.

31. Writing Formulas for Binary Covalent Compounds: Examples1
mono 2 di 3
tri 4
tetra 5
penta 6
hexa 7
heptaa 8
octa 9
nona 10
deca
* Second element in ‘ide’ from
* Drop –a & -o before ‘oxide’
nitrogen dioxide
NO2
diphosphorus pentoxide
P2O5
xenon tetrafluoride
XeF4
sulfur hexafluoride
SF6