1. Facts for Ionic Formulas

2. Simple Ionic Compounds
Concept:
Ionic Formulas are formed from positive and negative ions.
Fact 1:
Positive ions are formed by metals that lost electrons. These are cations.
Examples: Na1+ Mg2+ A3+ P4+
Ca+ion
aNion
Fact 2: Negative ions are formed by nonmetals that gained electrons. These are anions.
Examples: Cl O2- N3- Si4-
egative

3. Simple Ionic Compounds
Fact 3: We can predict the charges of the main group elements based on where they are on their families.
Lose 1e-
Gain 2e-
Gain 1e-
Lose 2e-
Lose 3e-
Gain 3e- +1 +3 -3 -2 -1 +2

4. Simple Ionic Compounds
Fact 4:
The overall charge of ionic compounds must equal zero.
Examples : Na1+ Cl1- Ca2+Br Al3+O2-

5. Lesson Two--Polyatomic Ion Formulas
Concept:
Polyatomic ions are groups of atoms that behave as one unit.
Fact 5:
Some ions have more that one atom. You will need to memorize most of these but some you can figure out from their atoms.
Examples: (SO4) = S +6 and O -8 = -2
(NO3)= N +5 and O -6 = -1
(NH4) = N -3 and H +4 = +1

6. Polyatomic Ion Formulas
Fact 6: These group ions, polyatomic ions, are treated like single ions in formulas, but must have parentheses when more than one is used in a formula.
Examples: Ca2+ and (NO3) 1- = Ca(NO3)2
Ga3+ and (SO4) 2- = Ga2(SO4)3
(NH4) 1+ and O2- = (NH4)2O
(NH4) 1+ and Cl1- = NH4Cl

7. Polyatomic Ion Formulas
Fact 7:
The polyatomic ions are named based on the atoms that they contain. Those with oxygen and another nonmetal are often name "____ate" with the root of the other nonmetal in the blank.
Examples: (NO3)1- is nitrate
(SO4)2- is sulfate
(ClO3) 1- is chlorate

8. Polyatomic Ion Formulas
Fact 8:
Those polyatomic ions with one oxygen less than the "ate" ions are named "----ite" ions.
Examples: (NO2) is nitrite
(SO3)2- is sulfite
(ClO2)1- is chlorite

9. Lesson Three--Transition Metal Compounds
Concept:
Transition metals have electrons in d orbitals and can donate different numbers of electrons, thus giving them several different positive charges.
Fact 9:
These can be determined from the Roman numeral which is written next to the metal's name.
Example: Cu1+is Copper I
Pb2+is Lead II
Fe3+is Iron III
Sn4+s Tin IV

10. Transition Metal Compounds
Fact 10:
These transition metals are used in formulas just like other metals, once the charge is determined from the Roman numeral in the name.
Example: Cu1+ Cl1- = CuCl Pb2+O2- = PbO
Fe3+Br1- = FeBr3
Sn4+O2- = SnO2

11. Transition Metal Compounds
Fact 11:
A few transition metal ions only have one charge and never change so they can be written without a Roman numeral in their formula name.
Example: Ag Zn2+ Cd2+

12. Lesson Four--Using Formulas in Problem Solving
Concept: Correctly written chemical formulas hold a large amount of information for the prepared student to find.
Fact 12:
The subscripts tell us the number of atoms of each kind that is present in the compound.
Example: NaCl has one atom of sodium and one atom of chlorine.
H2SO4 has two atoms of hydrogen, one atom of sulfur and four atoms of oxygen