1. Ionic compounds

2. What is a bond?
A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds them together.
Can be formed by atoms gaining, losing, or sharing electrons.
Why do atoms form chemical bonds?
To become more stable (lower potential energy)
ONLY valence electrons are used for bonding.

3. Ionic bonds
Atoms lose or gain electrons to satisfy octet (become more stable)
Form two kinds of ions—atom that has an electrical charge.
Cations—positively charged atoms.
Anions—negatively charged atoms

4. Periodic trends associated with ionic bonding
Ionization energy—energy required to remove an electron from the outer shell of an atom.
Electron affinity—the change in energy when an electron is added to the outer shell.
For bonding—High IE, high EA = less likely to give electrons = anion
Low IE, low EA = more likely to give electrons = cation
Need more convincing?
Draw orbital diagram for F.

5. Formation of Cations Atoms that lose electrons: Examples: Metals
Low IE—does not require a ton of energy to take an e- away
Low EA-does not readily accept other e- into outer shell.
Examples: Metals
Li, Na, K, Be, Mg, Ca, etc
Draw orbital diagrams for the following: Li Mg Al

6. Transition Metals
Form cations with different oxidation states (depends on what it’s bound to)
Titanium: [Ar]4s23d2
Can lose two electrons for Ti2+ or four electrons for Ti4+
Sometimes they will rearrange to have a pseudo-noble gas configuration (full outer shell, but not really)
Copper usually has its electrons fully rearrange to form [Cu]4s13d10 instead of [Cu]4s23d9

7. Formation of Anions Atoms that gain electrons:
High IE—requires a ton of energy to take an e- away
High EA-readily accepts other e- into outer shell.
Examples: Halogens and nonmetals
F, N, O, Cl, etc.
Draw orbital diagrams of the valence shells of the following: F S Br

8. Write the oxidation states for the following elementsMg Li P Ca Ba I K O S Cl N F

9. Ionic Bonds Held together by electrostatic force
Electrostatic force—force of attraction between positively and negatively charged particles

10. Crystal lattice What is it?
a 3 dimensional geometric arrangement of particles where + and – ions surround each other
the ions are packed into a regular repeating pattern that balances the forces of attraction and repulsion between the atoms

11. Crystal lattice Na Cl
- In a solid state, ionic compounds are non-conductors,
ions must be free to move for a current to pass
through it
- In a liquid state (molten) or when dissolved in water
they are good conductors (ions are free to move)

12. Lattice energy
The energy released when 1 mol of an ionic compound is formed from gaseous ions.
Endothermic—energy has to be absorbed for the rxn to happen
Surroundings are colder
Exothermic—energy is released (Ex: -436 kJ/mol)
Surroundings feel warmer since energy is given off
Which is more stable?

13. Formation of ionic compounds is almost ALWAYS exothermic Why
Formation of ionic compounds is almost ALWAYS exothermic Why??? More stable with lower potential energy

14. Formulas
Formula unit--represents the most simple ratio of the ions in an ionic compound
The total number of e-‘s gained by the nonmetal must equal the number lost by the metal atoms
Oxidation states—give insight into how the atom will bond
Used to determine the formula for a compound

15. Nomenclature What is it?? Rules for ionic nomenclature
The naming and writing of formulas for chemical compounds.
Rules for ionic nomenclature
1.) Cation is ALWAYS written first.
2.) Anion is ALWAYS written second.
3.) Use subscripts to cancel out charges

16. Nomenclature Naming Cation ALWAYS goes first.
If transition metal—write roman numeral to specify oxidation state
Anion ALWAYS goes second.
Monoatomic—drop suffix and add –ide
Polyatomic—use name of polyatomic ion

17. Practice Write the names for the following compounds: CaCl2 KF NH4Cl
Na2SO4
NH4NO3
MnO
MnO2

18. Practice Write the formulas for the following compounds:
Platinum (IV) chloride
Potassium bromide
Magnesium sulfate
Copper (II) chlorate
Silver (I) dichromate
Ammonium perbromate

19. Hydrides
Hydrogen can gain or lose one e- depending on what it binds with…
WHY?
When bonding with metals, H gains an e-
Since it is an anion, it gets the “-ide” suffix
Examples: LiH, MgH2, NaH, etc.

20. Hydrates Contain water in crystalline lattice
Can remove water without chemically altering substance
Nomenclature is the same as ionic compounds, except take water molecules into account.
How? Use prefixes to show number of water molecules

21. Practice
Name the following compounds:
NaCl∙2H2O
MgSO4∙7H2O
CuSO4∙5H2O
CoCl2∙5H2O
NiCl4∙3H2O

22. Practice Write the names for the following compounds:
Iron (II) fluoride tetrahydrate
Barium hydroxide octahydrate
Lead (II) perchlorate pentahydrate
Copper (II) acetate monohydrate
Tin (II) chloride dihydrate