Ionic & Covalent Bonds

A compound is a substance whose
smallest unit is made up of atoms of
more than one element bonded
together.


Compounds often have properties that
are different from the elements that
make them up.
For Example:
Water (H2O) and Hydrogen peroxide (H2O2)
• The
combining of atoms of elements
to form new substances is called
chemical bonding.
electrons in the outermost
shell are responsible for bonding.
• Exposed

Lewis Dot Structure (also called an
electron-dot configuration)
• Shows valence electrons as a series of
dots surrounding an atomic symbol.
•Find out which
group (column)
your element is in.
•This will tell you
the number of
valence electrons
your element has.
•You will only draw
the valence
electrons.

Atoms will combine to form compounds
in order to reach eight electrons in
their outer energy level.

Be aware that there are some exceptions!
CONSIDER EIGHT A
HAPPY NUMBER
FOR ATOMS!
◦ Atoms with less than 5 electrons tend to
lose electrons.
◦ Atoms with more than 6 electrons tend
to gain electrons.


In ionic bonding, electrons are
transferred between two or more
atoms.
Ion- is an atom having a
positive or negative charge.
atom that loses electrons
becomes a positive ion.
 The
 Has
more protons
than electrons.
atom that gains electrons
becomes a negative ion.
 The
 Has
more electrons
than protons.


The force of attraction between these
oppositely charged ions is an IONIC
BOND.
Ionic bonding occurs between a metal
and a nonmetal.



The charge that an atom would have if it lost
or gained electrons; ionic charge.
Can be helpful in determining which atoms will
interact or bond with each other.
Example:
According to electron dot diagram for Magnesium, it has
two valence electrons. Because Magnesium is “unhappy”
with two, it will typically lose them. If this happens it will
turn into a Magnesium ion. At this point it will have an
oxidation number of +2.
Mg :
Magnesium
Mg
2+
+
Na
+
Cl


In covalent bonding, electrons are
shared by two or more atoms.
Covalent bonding usually occurs
between atoms of nonmetals.

The force of attraction between the
nuclei of the atoms and the shared
electrons is a covalent bond.
 Molecule-
any group of atoms
held together by covalent bonds.
Ionic bonding

Attraction of
opposite charges

Between metal and
nonmetal

Ends in an ionic
compound
Covalent bonding

Formed from force of
attraction of nuclei
and electrons –
Sharing

Between nonmetals

Results in a molecule


The amount of energy needed to remove an
electron from an atom.
The closer the electron is to the nucleus,
the harder it is to remove.
•Weakest for
elements on the left
of the periodic table,
and strongest for
elements on the right