1. Demo Salt Crystal (hanging on ceiling)
Unit 5 Bonding
Lesson 1 – Ionic Bonds
Demo Salt Crystal (hanging on ceiling)
Videodisk Unit 3

2. Lewis Dot Diagrams Review
A way of showing atoms and how they bond
Atoms are represented by an atomic symbol with its valence electrons
Valence electrons depend on family
Li: 1s2, 2s1
N: 1s2, 2s2, 2p3
These are also called electron dot diagrams.
Typically, transition elements have 2 valence electrons. Li N

3. The Octet Rule
Atoms are most stable when their outermost shell is full
Level 1 = 2 electrons
All other shells = 8 electrons
Noble gases have full outer shell so they don’t bond with anyone
Other atoms lose, gain, or share electrons to get a full outer shell
For atoms to become more stable, they must lose energy. Full outer shells cause them to become stable (lose energy).

4. Ionic Bonding
Electrostatic attraction between ions of a metal and a nonmetal
Valence electrons are lost by metal, gained by non-metal Cl
Na NaCl
Ionic compounds are actually lots of + ions and – ions sticking together.
Properties
High melting points, brittle, dissolves in water, good conductors when liquid or dissolved.
Demo Salt Crystal
Link to Ionic bond animation

5. Metals lose electrons to get a stable outer shell (revert back to 8)
Nonmetals gain electrons to get a stable outer shell (add as many as needed until 8) K Cl
Final charges must equal zero.
K+ Cl-

6. Properties of Ionic Compounds
Most have high melting points and high boiling points.
Many dissolve in water. Most are brittle.
Good conductors of electricity if melted (molten) or dissolved.
Form crystalline structures.
Ionic bonds are usually strong and stable. If stressed, the bonds will break along a cleave line.
Ionic bonds are very strong and stable. But if stressed, will break along a cleave line.

7. Metal Cations Type I Type II
metals whose ions can only have one possible charge
IA, IIA, (Al, Ga, In, Zn, Cd, Ag)
determine charge by position on the Periodic Table
IA = 1+, IIA = 2+, (Al, Ga, In = 3+; Zn & Cd = 2+; Ag = 1+)
Type II
metals whose ions can have more than one possible charge
mostly transition metals, post-transition metals

8. Polyatomic Ions
Polyatomic ions are made of more than one atom. Polyatomic ions are groups of atoms that travel together—never apart. The given charge is on the entire polyatomic ion—not on individual atoms within the polyatomic ion. A list can be found on page 7 of your reference packet. You are responsible for knowing: ammonium, cyanide, acetate, nitrate, nitrite, hydroxide, carbonate, sulfate, sulfite, phosphate You will have a quiz on the names, symbols and charges of these polyatomic ions.

9. Naming Type I Metals Ionic Compounds
all names are composed of a cation (positive metal ion) and an anion (negative nonmetal ion or polyatomic ion)
Cation (metal) is element name
anion (nonmetal) is element name with –ide on the end or name of polyatomic ion
KCl
Potassium Chloride

10. Examples – Name the following
NaCl
MgO
Li3PO4
NH4Cl
Sodium Chloride
Magnesium Oxide
Lithium Phosphate
Ammonium Chloride

11. Formulas for Ionic Compounds
Balance the ions so the compound has a charge of zero
Magnesium Fluoride
Mg+2
F-1
We don’t typically write 1s.
Simplest form=Formula unit
MgF2
(Don’t Write 1s)

12. Formulas for Ionic Compounds
Balance the ions to zero
Silicon Sulfide
Si+4
(need 1 = +4)
S-2
(need 2 = -4)
We don’t typically write 1s.
SiS2
Simplest form =
Formula unit

13. Examples – Find the formulas of:
Calcium Oxide
Aluminum Chloride
Magnesium Nitrate
Ca O2-
CaO
Al Cl-
AlCl3
Mg NO3-
Mg(NO3)2

14. Extra Rules for Naming Ionic Compounds with a Type II Metal Ion
Type II metals are named like normal but with a Roman Numeral to indicate charge of the metal
Copper (I) = Cu+ Copper (II) = Cu2+
Name the following:
FeCl3
Each Chlorine has a charge of (-1). 3 chlorines would have a charge of (-3). To balance the compound to a charge of zero, Fe must have a charge of (+3); Iron (III)
Polyatomic ions are groups of atoms that travel together.
Iron (III) Chloride

15. Examples with Type II Metal Ions:
If there is one SO4 with a (-2) charge, the one Cu must have a (+2) to balance it
CuSO4
VCl5
FeO
Cu?+ SO42-
Copper (II) Sulfate
If there are five Cl’s with a (-1) charge each, the one V must have a (+5) to balance the (-5) from Chlorine
V?+ Cl-
Vanadium (V) Chloride
If there is one O with a (-2) charge, the one Fe must have a (+2) to balance it.
Fe?+ O2-
Iron (II) Oxide