Ionic Compounds
Definition: a compound made of
oppositely charged ions
Properties:
-formed by the reaction of a metal with
a nonmetal.
-Brittleness: tend to be brittle solids at
room temperature. This property is due to
the crystal lattice structure (repeating 3D
pattern)
-When an ionic compound is hit,
the pattern of ions shifts. Ions that have the
same charge line up and repel one another,
which cause the crystal to break.
High Melting Points: due to the strong
ionic bonds.
Covalent Compounds
Definition: the combining of atoms to
form molecules or compounds
Properties:
**Most compounds are covalent.
-Sharing of electrons
-A covalent bond is a weaker attractive
force than an ionic bond is.
-The group of atoms that make up a
covalent compound is called a molecule.
(the smallest particle into which a
covalently bonded compound can be
divided and still be the same compound).
Low Melting Points: Less heat is needed
to separate the molecules, so these
compounds have much lower melting and
boiling points.
Low Solubility: Many covalent
Solubility & Electrical Conductivity:
-Since they are highly soluble, ionic
compounds are not soluble which means
compounds dissolve in water.
they do not dissolve in water.
- Water molecules attract each of the ions -Most covalent compounds will not
of an ionic compound and pull the ions
dissolve in water because the attraction of
away from one another. The solution that
the water molecules to each other is much
forms when an ionic compound dissolves
stronger than the attraction of the water
in water can conduct an electric current
molecules to the compound.
because the ions are charged and are able to
-Example: olive oil is made of very large
move more freely past one another.
covalent molecules that do not dissolve in
water.
Electrical Conductivity: the covalent
compounds that do dissolve in water form
uncharged solutions.
-Sugar is a covalent compound that
dissolves in water and that does not form
ions.