1. Molecular Compounds & Acids
Naming
Molecular Compounds & Acids

2. Molecules Molecule – two or more atoms covalently bound together
Diatomic element – two of the same atom bound together

3. Diatomic Molecules The Magnificent 7 These atoms never exist alone.
Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodine
These atoms never exist alone.
When in the elemental form, they occur as a pair
For example:
Br  Br2
I  I2
N  N2
Cl  Cl2
H  H2
O  O2
F  F2

4. Binary Molecular Compounds
Binary covalent compounds contain 2 nonmetals
Before you can name binary covalent compounds, you MUST know the prefixes!
Mono Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca 1 2 3 4 5 6 7 8 9 10

5. Rules for naming Binary Covalent Compounds
Name the prefix for the number of atoms of the first element
Then name the first element
Name the prefix for the number of atoms of the second element
Than name second element with the ending -ide

6. Note… If the 1st prefix is mono….DROP IT!
Example:
CO = carbon monoxide NOT monocarbon monoxide
When the prefix ends in an o or a, and the name of the element begins with an o or a, one o or a is often dropped
CO = carbon monoxide NOT carbon monooxide

7. Examples What is the name of N2O4? N2  di nitrogen O4  tetra oxide
Since oxide begins with a vowel, we will
drop the a in tetra
Dinitrogen tetroxide

8. More examples Name SO2 S  mono sulfur
But mono is with the 1st element, so it will be dropped  sulfur
O2  dioxide
Sulfur dioxide

9. More examples Write the formula for dichlorine monoxide
Dichlorine  Cl2
Monoxide  O
Cl2O

10. More examples Write the formula for disulfur dichloride Disulfur  S2
Dichloride  Cl2
S2Cl2

11. Rules for Writing Formulas
Two sets of rules, ionic and covalent
To decide which to use, decide what the first word is.
If is a metal or polyatomic ion use ionic.
If it is a non-metal use covalent.

12. Hydrates Some compounds trap water crystals when they form.
These are hydrates.
Both the name and the formula needs to indicate how many water molecules are trapped.
In the name we add the word hydrate with a prefix that tells us how many water molecules.

13. Hydrates
In the formula you put a dot and then write the number of molecules.
Calcium chloride dihydrate = CaCl2·2H2O
Chromium (III) nitrate hexahydrate = Cr(NO3)3· 6H2O

14. Acids Acids can be recognized because the start with H
Acids are in aqueous solution (aq)
Examples
HCl (aq)
H2SO4 (aq)
HI (aq)

15. Rule #1 - naming acids
If the anion ends in –ide, the acid will be named…
Hydro (root) – ic acid
Examples:
HCl = Hydrochloric acid
HI = Hydroiodic acid
H2S = Hydrosulfuric acid

16. Rule #2 – naming acids
If you have an H plus an anion ending in –ate, the acid will be named…
(root) – ic acid
Examples
H2SO4 (sulfate) = Sulfuric acid
HNO3 (nitrate) = Nitric acid
H3PO4 (phosphate) = Phosphoric acid

17. Rule # 3 – naming acids
If you have an H plus an anion ending in –ite, the acid will be named…
(root) – ous acid
Examples:
H2SO3 (sulfite) = Sulfurous acid
HNO2 (nitrite) = Nitrous acid
H3PO3 (phosphite) = Phosphorous acid

18. Remember…
ate  ic
ite - ous

19. Writing formulas for acids
Look at the charge of the anion, and add Hyrogen ions (1+) to cancel it out
Example: Carbonic acid
Acid ends in –ic, so anion ends in –ate
Anion = carbonate (CO32-)
Formula = H2CO3

20. Examples
Hydrobromic acid
HBr
Chloric acid
HClO3

21. More examples H2SO3 H2CO3 HF Nitrous acid Perchloric acid Iodic acid
Sulfurous acid
Carbonic acid
Hydrofluoric acid
HNO2
HClO4
HIO3

22. Mixed examples (remember to figure out what type of compound it is 1st
KClO2
CO2
H2SO4
NH4Br
CuCO3
Fe2O3
HClO
Potassium chlorite
Carbon dioxide
Sulfuric acid
Ammonium bromide
Copper (II) carbonate
Iron (III) oxide
Hypochlorous acid

23. More Mixed Examples Carbon tetrachloride Phosphorous pentachloride
Aluminum oxide
Copper (II) nitrate
Chlorous acid
Hydrophosphoric acid
Iron (III) hydroxide
CCl4
PCl5
Al2O3
Cu(NO3)2
HClO2
H3P
Fe(OH)3