1. Chemical Bonding
Chapter 13

2. Electrons and Chemical Bonding
section 1

3. Combining Atoms Through Chemical Bonding
All substances are made of atoms of one or more the approximately 100 elements
carbon, hydrogen, and oxygen combine
to make sugar, alcohol and citric acid
chemical bonding is the joining of
atoms to make new substances

4. properties of these new substances are different from the original substances
An interaction that holds 2 atoms together is called a chemical bond
Chemical bonds form when electrons are gained, lost, or shared

5. Discussing Bonding Using Theories and Models
atoms and chemical bonds cannot be
seen with the unaided eye
for 150 years scientists have done
experiments to help develop theories
of chemical bonding
models used to help form theories

6. Electron Number and Organization
To understand how chemical bonds form, you need to know about the electrons
Electrons in an atom are organized in energy levels
models are useful for
counting electrons in
energy levels

7. Outer Level Electrons and Bonding
Not all of the electrons in an atom can
make chemical bonds
Atoms bond using only the electrons
in the outer most energy level
valence electrons are the electrons in
the outer most energy level

9. Valence Electrons and the Periodic Table
You can use the periodic table to
determine the number of valence
electrons of some elements
Elements are grouped by similarities
within group there are the same
number of valence electrons
Group numbers can help determine
the number of valence electrons

11. To Bond or Not To Bond
Not all atoms bond in the same way
The number of electrons in the outer
energy level will determine whether
an atom will bond
Noble gases usually don't form
chemical bonds
have 8 valence electrons
(except for Helium)
outer level is considered full
if it has 8 valence electrons

12. Filling the outermost level
an atom with fewer than 8 valence
electrons is more likely to form bonds
atoms bond by gaining, losing or
sharing electrons to have a filled
outer most energy level

13. Is Two Electrons a Full Set?
Not all atoms need 8 valence electrons
Helium only needs 2
Hydrogen, and lithium can form bonds
with only 2 valance electrons

14. Valence Numbers vs. Oxidation Numbers
Valence number= is the number of
electrons in the outer energy level
Oxidation number = is the number
of electrons it will give or take
Na O
valence- 1 valence - 6
oxidation +1 oxidation -2