Chemical Bonding
Ionic Bonding and
Ionic Compounds
Ionic Bonding and Ionic Compounds
Objectives:
1. Compare and contrast a chemical formula for a
molecular compound with one for an ionic
compound.
2. Discuss the arrangement of ions in crystals.
3. Define lattice energy and explain its significance.
4. List and compare the distinctive properties of ionic
and molecular compounds
5. Write the Lewis structure for a polyatomic ion.
Ionic Bonding and Ionic Compounds
Ionic Compound – positive
and negative ions combined
is such a way to yield a
neutral compound.
H 2O
Formula unit – simplest
ratio of atoms found in an
ionic compound
NaCl
Formation of Ionic Compounds
Ionic compounds form as a result of the transfer
of elecrons.
Formation of Ionic Compounds
Formation of Ionic Compounds
• Cations and anions are
arranged in a crystal
lattice; minimizing
potential energy
• Arrangement among ions
represents a balance
between attractive and
repulsive forces
• Lattice energy – energy
released when an ionic
compound forms.
CaF2
Properties of Ionic Compounds
Some common properties result form the strong forces
of attraction holding the basic units together.
• High melting and boiling points
• Hard, but brittle substances
• Do not conduct electricity in the solid state.
• Do conduct electricity in molten state.
• Many dissolve in water and conduct electricity
• Others…do not dissolve in water.
Polyatomic Ions
• Group of covalently bonded atoms that have acquired
a positive or negative charge and form bonds with
other ions.
Draw Lewis structures for:
NH4+
NO3—
SO42-
PO43-