1. Molecular Compounds & Acids
Naming
Molecular Compounds & Acids

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

3. Diatomic Elements H, N, O, F, Cl, Br, I or the Magnificent 7
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These elements exist as diatomic molecules in their most stable state.
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
No Polyatomic Ions!!!!!
No Charges!!!!

5. Naming Binary Covalent Compounds
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

6. Rules for naming Binary Covalent Compounds ex. N2F4
Name the prefix for the number of atoms of the first element (ex. Di-)
Then name the first element (ex. Dinitrogen)
Name the prefix for the number of atoms of the second element (ex. Dinitrogen tetra-)
Than name the root of the second element with the ending –ide
(ex. Dinitrogen tetrafluoride)

7. Note… If the 1st prefix is mono….DROP IT!
Ex. CO is carbon monoxide NOT monocarbon monoxide
When the prefix ends in an o or a, and the name of the element begins with a vowel, the o or a is often dropped
EX. CO4 would be carbon tetroxide NOT carbon tetraoxide

8. 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

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

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

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

12. Acids Acids can be recognized because the start with H Examples HCl
H2SO4 HI

13. Acids Acids are in aqueous solution (aq)
For the purposes of this class, we will assume that if it begins with H, we will name it according to the rules of naming acids

14. 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

15. 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
Sulfuric acid
HNO3
Nitric acid
H3PO4
Phosphoric acid

16. 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
Sulfurous acid
HNO2
Nitrous acid
H3PO3
Phosphorous acid

17. Writing formulas for acids
When writing formulas for acids you MUST look at the charges of the anion and add as many hydrogens as needed to cancel out the negative charge (because hydrogen is +1)
Example: Phosphoric acid
Phosphate = PO4-3
So, phosphoric acid = H3PO4

18. Remember…
ate  ic
ite - ous

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

20. Rules for Writing Formulas
Three sets of rules, ionic, covalent, and acids
To decide which to use, decide what the first substance is.
If is a metal or polyatomic ion use ionic.
If it is a non-metal use covalent.
If it is hydrogen, use acid rules

21. 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.

22. 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

23. 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

24. 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