1. Ionic Bonding
Formation of IONS

2. ATOMS Are electrically neutral (no charge)
# electrons = # protons (atomic number)

3. IONS – charged particles
IONS are atoms that have gained or lost electrons.
Since the # electrons is no longer = # protons the atom carries a charge.
Charge on the ion = # protons - # electrons

4. IONS Cation Anion positive negative
If the atom loses electrons, it’s going to have more positive charge than negative. What kind of ion is it?
If the atom gains electrons, it’s going to have more negative charge than positive. What kind of ion is it?
positive
Cation
Anion
negative

5. Charge of Ions
If we want to specify an ion, we write the charge as a right superscript.
Cl-1 a chloride ion with a charge of -1.
Na+1 a sodium ion with a charge of +1.
O-2 an oxide ion with a charge of -2.
If there is no right superscript, it is understood to be zero and a neutral atom.
This right superscript is also called the oxidation number.

6. Oxidation Number from Periodic Table

7. Oxidation Number
These numbers are assigned to keep track of electron gain or loss.
Oxidation numbers (states) are given on the upper right hand corner of the periodic square for each element.
What is the oxidation number of K? …of F? …of Cl?
The first (top) number given in the most common oxidation state. The other oxidation numbers are also possible.
Note: Nonmetals tend to have multiple oxidation states while group 1 and 2 metals have only one oxidation state.

8. Lewis Structures of Atoms
Symbol and dots for valence electrons
Na has 1 valence electron:
Cl has 7 valence electrons:
Na•
Memory Jogger   Cl  

9. Lewis Structures of Ions
Positive ions have NO valence electrons.
Negative ions have 8 valence electrons.
Use brackets and right superscript to show CHARGE!
Sodium ion is Na1+
Chloride ion is :Cl: 1- .. ..

10. Lewis Diagrams: Ionic Compounds
NaCl has the Lewis structure:
[Na]1+ [ Cl ]1- • • • • • • • •
Lewis Structures for compounds show the
valence electrons after the transfer!

11. Naming Ions Metals (Cations)
Full name of the metal followed by the word cation.
Calcium Cation
Or…
Calcium Ion
Nonmetals (Anions)
Name of the non- metal with “ide” followed by the word anion.
Fluoride Anion
Or…
Fluoride Ion

12. Isoelectronic Species
Atoms or ions that have the same electronic configuration are called an isoelectronic species.
same configuration as the nearest noble gas.
Period 3 representative elements all having 10 electrons:
Na1+ Mg2+ Al3+ N3- O2- F1- Ne0
Atomic number increases, radius decreases – Why?