Grade 10 Academic Science – Chemistry
Chemical Nomenclature
Science Perspectives 10 – Section 5.7 Pages 196-200
Every element has its own chemical symbol (one or two letters) which stands for that chemical's
name.
For example, hydrogen is an element. It is a colorless gas, lighter than air, and explodes if a
spark hits it. The letter H is always hydrogen.
Why bother to have symbols for the elements?
The elements are the building blocks of all matter. Elements are put together to make
compounds. To describe compounds, we can combine the chemical symbols. A group of
symbols showing what elements make up a compound is known as a chemical formula.
For instance, water is a very common compound. A molecule of water has two atoms of
hydrogen and one atom of oxygen. Thus, the chemical formula for water is H2O.
The chemical formula for acetylsalicylic acid, otherwise known as aspirin, is C 9H8O4. It is a
molecule with nine atoms of carbon, eight atoms of hydrogen and four atoms of oxygen.
Task
Answer each question
1. NaHCO3 is baking soda. Using this formula as a guide, name the four different elements
which make up a molecule of baking soda.
2. The chemical formula for sulfuric acid is H2SO4. List the symbols of different elements in
a molecule of this compound, and then, tell how many atoms of each element are in the
molecule.
3. The chemical formula for carbon dioxide is CO2. Name the elements which make up the
molecule AND tell how many atoms of each element are in the molecule.
4. A molecule of potassium permanganate is written as KMnO4. Name the different
elements in a molecule of this compound, and then, tell how many atoms of each
element are in the molecule.
5. Pentachlorophenol is C6Cl5OH. List the symbols of different elements in a molecule of
this compound, and then, tell how many atoms of each element are in the molecule.
6. C12H4Cl4O2 is the chemical formula for a very dangerous chemical byproduct called
2,3,7,8-tetrachloro-dibenzo-p-dioxin. Name the different elements in a molecule of this
compound, and then, tell how many atoms of each element are in the molecule.
7. Sodium chloride is NaCl. Name the different elements in a molecule of this compound,
and then, tell how many atoms of each element are in the molecule.
Naming Ionic Compounds
Many ionic compounds are made up of two elements: a metal and a non-metal. In these cases,
the compound name identifies both parts
 The FIRST PART refers to the cation (metal). Its name does NOT change.
 The SECOND PART is the anion (non-metal). The name changes to a suffix of “ide.”
Table 1. Examples of Ionic Compound Names
Metal
Non-metal
Compound Name
Sodium
Chlorine
Sodium chloride
Aluminum
Oxygen
Aluminum oxide
Potassium
Sulfur
Potassium sulfide
Task

Using a Periodic Table, determine the Ionic Charge and the Ion Symbol for the listed
elements in Table 2
Table 2. Ionic Charges and Ion Symbol
Ionic
Element
Ion Symbol
Charge
Fluorine
F-
-1
Chlorine
Oxygen
Sulfur
Phosphorus
Nitrogen
Quick Question – The Ion Symbol for Selenium is Se-2. What does the symbol tell you?
Chemical Formula
Zero-Sum Rule
 The sum of all charges in the chemical formula of the Ionic Compound must equal zero
(see Page 197).
Task
 Complete the table for each compound listed
Step
Metal
Non-metal
Metal
Element
Symbol
Al
O
Ionic Charge
for Element
+3
-2
Number of
Ions needed
to make total
charge zero
2
3
Chemical
Formula
Al2O3
Ca
Non-metal
Metal
Non-metal
Cl
Na
Cl
 Complete the table for each compound listed
Step
Metal
Non-metal
Metal
Element
Symbol
Mg
Br
K
Non-metal
Metal
Non-metal
S
Mg
O
Ionic Charge
for Element
Number of
Ions needed
to make total
charge zero
Chemical
Formula
Elements with Multiple Charges
Some elements have more than one stable cations (see Table 3). These ions are named like
other cations. However, the Roman Numeral inside the round brackets indicates the IONIC
CHARGE of the metal (…not the number of ions).
Table 3. Names and Multiple Ionic Charges for Common Metals
Metal
Chemical Symbol
Chemical Symbol
Names of Ions
for Element
for Ions
Copper
Iron
Cu
Fe
Cu+
Copper (I)
Cu2+
Copper (II)
Fe2+
Fe3+
Lead
Pb
Pb2+
Pb4+
Manganese
Mn
Mn2+
Mn4+
Tin
Sn
Sn2+
Sn4+
Why do the elements noted in Table 3 have multiple charges?
 These elements are TRANSITION METALS. As noted in Table 3, the ion has a positive
charge (cation). As we know, cations have low ionization energy. Transition metals have
very low ionization energy. What is the likely impact of very low ionization energy?
 To make it more complicated, the electron configuration of transition metals is different.
The electrons used to combine with other elements (i.e., their valence electrons) are
present in more than one shell. That is, the electron shells are partially full, and thus,
multiple ion charges are possible.
HOMEWORK
 Page 200 Questions 2-10