South Pasadena • Chemistry
Name
4 · Salts and Solutions
Period
4.1
NOTES
–
Date
NAMING COMPOUNDS
Review: Types of Compounds
 Ionic Compounds – cation (usually metal ion) and anion
e.g. MgCl2
 Covalent Compounds – made of non-metal atoms
e.g. NO2
 Organic Compounds – starts with CH
e.g. C2H5OH
 Acid – starts with H; H+ and anion
e.g. HNO3
We are going to focus on naming ionic and covalent compounds in this lesson, and acids in lesson 4.4. We should
be very fluent with our ions by this point, or this unit will be very difficult.
Ionic Compounds
Salt: any ionic compound. Table salt is specifically NaCl.
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Ionic Compounds are typically hard solids with high melting points.
If an ionic compound dissolves in water, it’s said to be soluble and breaks up into ions.
In an ionic compound, the positive and negative charges cancel out to for a neutral compound.
o If you use more than one of one ion, use subscripts.
o If you use more than one of a polyatomic ion, use parentheses.
To name an ionic compound, write the name of the cation and the anion.
Task 1 – Forming Ionic Compounds
Number of positive and negative charges must be the same. Use parentheses if you need more than one copy of a polyatomic
ion. No prefixes ever!
Cation Anion
Chemical Formula
Name
Ca2+
O2–
CaO
Calcium oxide
Ca2+
Cl–
CaCl2
Calcium chloride
Ca2+
NO3–
Ca(NO3)2
Calcium nitrate
Ca2+
PO43–
Ca3(PO4)2
Calcium phosphate
Task 2 – Decomposing Ionic Compounds
Identify the anion first because the cation may have several possible charges.
Chemical Formula
Cation
Anion
Name
Na2O
Na+
O2−
Sodium oxide
Al(C2H3O2)3
Al3+
C2H3O2−
Aluminum acetate
CuCl2
Cu2+
Cl−
Cupric chloride or copper(II)
chloride
Note: the “2” for chloride is because
we have 2 chloride ions, not because
chlorine is diatomic.
FeCO3
Fe2+
CO32−
Ferrous carbonate or
iron(II) carbonate
Covalent Compounds
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Covalent compounds can be solids, liquids, or gases at standard states, and usually have much lower melting points.
The electrons in a covalent compound may be unevenly distributed, resulting in a polar compound.
Polar compounds dissolve better in water than nonpolar compounds. However, they do not form ions.
To name covalent compounds, state the non-metal elements. The last element should be changed to have an “-ide”
suffix.
Use a prefix for each element (unless there is only one of the first element).
# Prefix
# Prefix
# Prefix
# Prefix
1 mono4 tetra7 hepta10 deca2 di5 penta8 octa3 tri6 hexa9 nona-
Examples:
 XeF4
xenon tetrafluoride
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P4O10
tetraphosphorus decoxide
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Dinitrogen monoxide
N2O
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Oxygen dichloride
OCl2