1. Nomenclature
Chapter 2

2. Chemical Formulas Formula Unit: Molecular formula: Empirical formula:
Identifies exact number of atoms in an ionic compound
Molecular formula:
Identifies exact number of atoms in a covalent molecule
Empirical formula:
Shows the simplest whole number ratio of atoms in a compound
H2O
molecular
empirical
C6H12O6
CH2O O3 O
N2H4
NH2

3. 7 DIATOMIC ELEMENTS HOFBrINCl
Some elements do not like to be alone… so they bond to themselves! 7
HOFBrINCl

4. The ionic compound NaCl
Ionic Compounds
consist of a combination of cations and anions formed from a transfer of electrons
the formula unit is always identical to the empirical formula
the sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero
The ionic compound NaCl

5. NAMING BINARY IONIC COMPOUNDS
RULE 1
Metal – Nonmetal
Write the metal (positive ion) first
Change the ending of the second word to -ide

6. Rule 1 Examples KBr CaBr2 LiF Li2O MgO BaS K3P Na3N Potassium Bromide
Calcium Bromide
Lithium Fluoride
Lithium Oxide
Magnesium Oxide
Barium Sulfide
Potassium Phosphide
Sodium Nitride

7. NAMING COMPOUNDS WITH POLYATOMICS
RULE 2
Polyatomic Ions
DO NOT CHANGE ANYTHING!
When you have NH4 and a single element, change the second word to -ide

8. Rule 2 Examples Ba(SO4) Ba(SO3) Na2(CO3) Na(HCO3) (NH4)3(PO4)
(NH4)(OH)
Barium Sulfate
Barium Sulfite
Sodium Carbonate
Sodium Bicarbonate
Ammonium Phosphate
Ammonium Hydroxide

9. Formula of Ionic Compounds
2 x +3 = +6
3 x -2 = -6
Al2O3
Al3+
O2-
1 x +2 = +2
2 x -1 = -2
Ca Br2
Ca2+
Br-
1 x +2 = +2
1 x -2 = -2
Na2CO3
Na+
CO32-

10. NAMING COMPOUNDS WITH TRANSITION METALS
RULE 3
Transition Metals
Can have more than one type of charge
Write the charge number in roman numerals

11. Rule 3 Examples Cu2O CuO FeCl2 FeCl3 SnCl4 Mn2O3 PbS Copper (I) Oxide
Copper (II) Oxide
Iron (II) Chloride
Iron (III) Chloride
Tin (IV) Chloride
Manganese (III) Oxide
Lead (II) Sulfide

12. FeCl3 • 6H2O = Iron (III) Chloride Hexahydrate
NAMING HYDRATES
What is a hydrate?
Hydrates are named:
Compound • Prefix-Hydrate
FeCl3 • 6H2O = Iron (III) Chloride Hexahydrate

13. Name to Formula – Criss Cross Rule
Lithium Fluoride
Sodium Sulfide
Aluminum Bromide
Iron (III) Oxide
Carbonic Acid
Calcium Carbonate
Magnesium Acetate
Copper (II) Sulfate Pentahydrate
Ammonium Sulfite
Barium Hypochlorite

14. Covalent Compounds Referred to as molecules
Consists of nonmetals covalently bonded
nonmetals or nonmetals + metalloids
Least electronegative element is usually written first

15. NAMING COVALENT COMPOUNDS
RULE 4
Nonmetal – Nonmetal
USE PREFIXES!
Change the ending of the second word to -ide
No mono on the first word
Drop any double vowels
TOXIC!
NO2
nitrogen dioxide
N2O
dinitrogen monoxide
Laughing Gas

16. Prefixes
Number of Atoms
Prefixes 1 2 3 4 5 6 7 8 9 10

17. Rule 4 Examples CO CO2 SO2 SO3 N2H4 N2O3 PCl3 SiO2 P2O5 CS2 Al2O3
Carbon Monoxide
Carbon Dioxide
Sulfur Dioxide
Sulfur Trioxide
Dinitrogen Tetrahydride
Dinitrogen Trioxide
Phosphorus Trichloride
Silicon Dioxide
Diphosphorus Pentoxide
Carbon Disulfide
Aluminum Oxide

18. ACIDS
a substance that yields hydrogen ions (H+) when dissolved in water.
example: hydrochloric acid refers to a water solution of the molecular compound hydrogen chloride, HCl
Many polyatomic ions are produced by the loss of hydrogen ions from oxyacids.
Acid Name: Polyatomic Ion:
sulfuric acid H2SO4 sulfate
nitric acid HNO3 nitrate
phosphoric acid H3PO4 phosphate

19. NAMING ACIDS
Binary acids: consist of two elements, usually hydrogen and a halogen
“HX”
Oxyacids: contain hydrogen and a polyatomic ion (usually oxygen and a third nonmetallic element)
“HXO”

21. NAMING BASES NaOH sodium hydroxide KOH potassium hydroxide Ba(OH)2
Base: a substance that yields hydroxide ions (OH-) when dissolved in water.
NaOH
sodium hydroxide
KOH
potassium hydroxide
Ba(OH)2
barium hydroxide