Chemical Bonding
Chemical Bond

A force that holds two or more atoms
together
◦ This happens because atoms prefer to have a
full outer shell
◦ Atoms can share, lose, or gain valence
electrons
Atoms want to be STABLE
Atoms are stable when their outer most
energy level is full
 Unstable atoms have spaces in their outer
energy level

◦ All atoms are unstable alone except for which
group?
 Noble Gases

Because most are unstable alone, they
combine with others to become stable
How do atoms Bond?
Ionic bonds
 Covalent bonds

How will we represent bonds?
By using Lewis Dot Diagrams
 Only concerned with valence electrons!!

Question

Which electrons are we concerned with
during bonding?
Lewis Dot Diagram Refresher

Draw the diagram for:
◦
◦
◦
◦
◦
Beryllium
Aluminum
Tin
Bismuth
Radon
Ionic Bonds

When atoms become stable by either giving
or taking electrons from another atom
◦ Most often a metal and a non-metal bond

Neutral atom- if # of protons and # of
electrons are equal

Ion- an atom that has gained or lost
electrons
◦ Ions have electrical charges
Question
Most of the atoms on the periodic table
are neutral. (T/F)
 Most of the time, which two types of
elements are bonding together in an ionic
bond?(metal and non-metal/ non-metal
and non-metal/ metal and metal)

Ions

Cation- an atom that loses electrons
◦ Have positive charges
◦ Na+

Anion- an atom that gains electrons
◦ Have negative charges
◦ Cl-

Opposites Attract!!
◦ Atoms with opposite charges bond together
Question
What is an ion?
 O ++ is an example of (anion/cation)


How/why do ionic bonds form?
Covalent Bonds

When two atoms share their outer
energy level by sharing a pair of electrons
◦ Most often a non-metal and a non-metal bond

Both atoms keep their valence electrons

Charges don’t change, but they become
stable