1. Naming covalent compounds and
acids
Lisa Allen
Stonington High School
Honors chemistry

2. How do you know the compound
is covalent?
1. The compound is called a molecule. Molecules are
covalently bonded.
2. The compound doesn’t start with a metal or with
ammonium.
3. The compound is made from elements that are
similar in electronegativity
4. Organic compounds often have carbon for their first
element, and that is going to form covalent bonds.
These frequently use another naming system you will
learn in organic chemistry!

3. To name covalent compounds, use
prefixes
 1- mono
 2- di
 3 – tri
 4 – tetra
 5 – penta
 6 – hexa
 7 – hepta
 8 – octa
 9 – nona
 10 - deca

4. Simple rules
 Write the name of the less
electronegative element first.
 If you have more than one atom of that
element in the compound, you will need
a prefix before its name. If not, skip the
prefix here.
 Always put a prefix before the name of
the more electronegative element.
 Change the ending of the second
element to –ide.

5. Practice a few of these
 CO
 P2O5
 OF2
 SO2
 SO3
 N2O5
 N2O4
 H2O

6. Practice a few of these
 CO  Carbon monoxide
 P2O5  Diphosphorus
 OF2
pentoxide
 Oxygen difluoride
 SO2
 Sulfur dioxide
 SO3
 Sulfur trioxide
 N2O5
 Dinitrogen pentoxide
 N2O4
 Dinitrogen tetroxide
 H2O
 What??

7. What are some of the dangers associated with DHMO?
Each year, Dihydrogen Monoxide is a known causative component in many thousands of deaths and is a major contributor to millions upon
millions of dollars in damage to property and the environment. Some of the known perils of Dihydrogen Monoxide are:
•Death due to accidental inhalation of DHMO, even in small
quantities.
•Prolonged exposure to solid DHMO causes severe tissue
damage.
•Excessive ingestion produces a number of unpleasant
though not typically life-threatening side-effects.
•DHMO is a major component of acid rain.
•Gaseous DHMO can cause severe burns.
•Contributes to soil erosion.
•Leads to corrosion and oxidation of many metals.
•Contamination of electrical systems often causes short-
circuits.
•Exposure decreases effectiveness of automobile brakes.
•Found in biopsies of pre-cancerous tumors and lesions.
•Given to vicious dogs involved in recent deadly attacks.
•Often associated with killer cyclones in the U.S. Midwest
and elsewhere, and in hurricanes including deadly storms in
Florida, New Orleans and other areas of the southeastern
U.S.
•Thermal variations in DHMO are a suspected contributor to
the El Nino weather effect.
http://www.dhmo.org/facts.html

8. Naming acids
Acids are (almost) always compounds made from
hydrogen and an anion.
 Hydrogen plus a halogen?  hydroXXXic acid
 Example: HCl = hydrochloric acid
 Hydrogen plus a polyatomic ion that ends in –ate?
 XXXic acid
 Example: Hydrogen plus nitrate is HNO3 = nitric acid
 Hydrogen plus a polyatomic ion that ends in –ite?
 XXXous acid
 Example: Hydrogen plus nitrite is HNO3 = nitrous acid

9. How many hydrogens do you add
to the anion to make the acid
formula?
 Each H+ has a +1 charge, so add one for every
negative charge.
 Nitric acid only needs one, since nitrate is a -1
ion.
 Sulfuric acid is H2SO4 since sulfate has a 2-
charge.

10. The big conclusion?
IONIC COVALENT ACIDS
COMPOUNDS COMPOUNDS
Hydrogen is the first
Include a metal and a Made from two non- element
non-metal, or metals H + halogen = hydroXic
ammonium and a non- Use prefixes when acid
metal naming H + ate = ic acid
May include Second element always H + ite = ous acid
polyatomic ions gets a prefix, even if it is
No prefixes used mono-
D-block cations need
a Roman numeral
Naming system is
called “the Stock
system”