1. Chapters 3 Ionic Compounds

2. Octet Rule
Octet Rule: the tendency for atoms to achieve 8 electrons in their valence shell
Natural electron configuration of the Noble Gases
Done by gaining, losing, or sharing electrons
Increases stability, less chance to react afterwords
H and He seek a “Duet”
Na = [Ne]3s1  Na+ = [Ne]
Cl = [Ne]3s23p5  Cl- = [Ne]3s23p6 = [Ar]

3. To gain or to lose electrons?
Goal is to achieve a noble gas electron configuration
Metals lose electrons
Nonmetals gain electrons
Its easier for a nonmetal (Ex: chlorine) to gain 1 electron vs losing 7 electrons.
Its easier for a metal (Ex: magnesium) to lose 2 electron vs gaining 6 electrons.
To gain or to lose electrons?

4. Ionic Bonding
Ions: atoms that have a charge due to gain or loss of electrons
Anion: (-) charged atom – added electron(s)
Cation: (+) charged atom – lost electron(s)
Ionic Bond: a bond formed through the transfer of one or more electrons from one atom or group of atoms to another atom or group of atoms

5. Oxidation state
oxidation state/number – represents the number of electrons lost or gained by an atom of an element in that compound
It relates to the charge of the atom as well
If a sodium atom loses one electron it will have a positive charge and the oxidation state will be +1
If an oxygen atom gains two electrons it will have a negative charge and the oxidation state will be -2

6. Oxidation state
Formula Unit

7. Oxidation state

9. Ionic Compounds: compounds composed of oppositely charged ions that are held together by their attraction to each other
Metal + Non-metal
NaCl
Metal + Polyatomic Ion
NaNO3
Polyatomic Ion + Non-metal
NH4Cl
Polyatomic Ion + Polyatomic Ion
NH4NO3
Net charge on compound equal to zero

11. Oxyanions SO42- Sulfate SO32- Sulfite PO43- Phosphate PO33- Phosphite
NO3-
Nitrate
NO2-
Nitrite
ClO4-
Perchlorate
ClO3-
Chlorate
ClO2-
Chlorite
ClO-
Hypochlorite

12. Rules For Naming Ionic Compounds
Name the cation by its elemental/polyatomic name Na+Cl- = NaCl = sodium chloride
If the metal is a transition metal with a variable charge, use a Roman Numeral in parentheses for its charge FeCl2 = iron(II)chloride
Next, name the anion and change its ending to “-ide” Cl- = chloride
If the anion is polyatomic, do not change the ending to “-ide” NaNO3 = sodium nitrate
Do NOT use prefixes (mono, di, tri etc.) to indicate how many of each atom are present

13. Iron (III) Chloride
Iron (II) Chloride
FeCl3
FeCl2

14. Problems Write the name for the following compounds: KI MgBr2 Al2O3
FeCl2
CaSO4
Ba(NO2)2
Cu(NO3)2
potassium iodide
magnesium bromide
aluminum oxide
iron(II)chloride
calcium sulfate
barium nitrite
copper(II) nitrate

15. Write the Formula for the following ionic compounds: Sodium Fluoride
Calcium Sulfite
Calcium Chloride
Iron (III) Oxide
Cobalt (II) Hydroxide
Ammonium Bromide
Ammonium Carbonate
Aluminum Carbonate
NaF
CaSO3
CaCl2
Fe2O3
Co(OH)2
NH4Br
(NH4)2CO3
Al2(CO3)3

16. Chapter 3 checklist
Know how to write electron configurations for main group element ions
Know the octet rule and the duet exception
Know what kind of an ion an element will become based on its group number
Know what ionic bonding is
Know the oxidation state of an ion
Know how to find the charge of a transition metal based on the ion it is attached to
Know what an ionic compound is and how to make one
Know all the names, formulas and charge of the major polyatomic ions
Know how to name an ionic compound from the formula
Know how to produce a formula from the name of an ionic compound