1. Nomenclature

2. Ions: an atom or group of atoms with a positive or negative charge
Cation: an ion with a positive charge because electrons were lost (name the same as the element)
Anion: an ion with a negative charge because electrons were gained (name ending changes to “-ide”)

3. Cation Formation Sodium Atom Sodium Ion 1 e- 8 e- 2 e- 8 e- 2 e- 11 p+

4. Anion Formation Fluorine Atom Fluoride Ion 9 p+ 10 n0 9 p+ 10 n0 1 e-

5. Metal Ions Many transition metals have more than one type of ion
Transition metals with more than one type of ion are named using Roman numerals
Fe+2 is Iron (II)
Fe+3 is Iron (III)
Transition metals with only one ion are simply given the name of the cation
Silver is Ag+1
Cadmium is Cd+2
Zinc is Zn+2

6. Polyatomic Ions H O - H H - N - H H
A tightly bound group of atoms that acts as a unit and carries a charge
Names usually end in “-ate” or “-ite”
Has 8 electrons but should have 9 (5 from N and 4 from H), so there is one less electron than expected. +1 H -1
O - H
H - N - H H
Has 8 electrons, but it should have 7 (6 from O and 1 from H), so there is an extra negative charge.

7. Most used Polyatomic Ions:
Acetate
Chlorate
Cyanide
Hydroxide
Nitrate
Nitrite
Carbonate
Sulfate
Sulfite
Phosphate
Ammonium

8. Criss-Cross Method Do not write the charge (the + or -)
Do not write a subscript of (H2O, NOT H2O1)
Parenthesis MUST be used when a subscript is added to a polyatomic ion [Mg(OH)2, NOT MgOH2]
Subscripts MUST be in the lowest, whole-number ratio

9. Fe+3
O-2
Fe2O3
Ca+2
NO 3 -1
Ca(NO3)2
Fe+2
O-2
Fe2O2
FeO
Pb+4
O-2
Pb2O4
PbO2

10. Naming Ionic Compounds
Name the cation first
Name the anion second (end in “-ide”)
If the metal has more than one charge, use the Roman numeral to match the charge
If a polyatomic is present, look it up on your chart
Fe2O3
Iron (III) oxide
Mg(OH)2
Magnesium hydroxide
LiOH
Lithium hydroxide
FeO
Iron (II) oxide
PbO2
Lead (IV) oxide

11. Naming Acids Acids always begin with the element hydrogen.
You need to become familiar the following acids:
Hydrochloric Acid: HCl
Hydrofluoric Acid: HF
Hydrobromic Acid: HBr
Hydroiodic Acid: HI
Nitric Acid: HNO3
Acetic Acid: HC2H3O2
Sulfuric Acid: H2SO4
Carbonic Acid: H2CO3
Phosphoric Acid: H3PO4

12. Naming Molecular Compounds
Use prefixes:
1 = mono
2 = di
3 = tri
4 = tetra
5 = penta
6 = hexa
7 = hepta
8 = octa
9 = nona
10 = deca
Never use the prefix “mono” with the first element (carbon monoxide)
The ending of the second element will be “-ide”
CO2
PCl5
H2O
Carbon dioxide
Phosphorus pentachloride
Dihydrogen monoxide

13. Writing Formulas From Names
Are the elements 2 non-metals?
If yes, then there are prefixes.
Use the prefix to write the subscript for each element in the formula.
Phosphorus pentachloride
PCl5
Are the elements a metal & a non-metal?
If yes, then you need to determine the charge on each element.
Criss-cross the charges to find the formula.
Sodium sulfate
Na+1 and SO4 -2
Na2SO4

14. The Laws … The Law of Definite Proportions
In samples of chemical compounds, the masses of the elements are always in the same proportions.
The Law of Multiple Proportions
Whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.