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Student Resource Sheet AC - 12
IT’S ELEMENTARY!
You have learned that there are over 109 naturally occurring elements and a growing list of manmade elements. With so many different elements combining to make a countless number of
compounds, this task can seem overwhelming. As a result scientists have found a way to
organize these elements based on similar characteristics. Elements are organized on the Periodic
Table of the Elements. By knowing how the periodic table is organized, you can make
predictions about the properties of these elements and their ability to form the compounds in our
world.
Objective:
When you have completed this investigation, you should be able to
1.
Interpret the layout of the periodic table in order to explain how it is organized.
Materials:
Periodic Table of the Elements
Activity 1: Atoms and the Periodic Table
USING THE PERIOIDIC TAB LE
Scientists all over the world use the same symbols for the elements. Chemical symbols
are a shorthand way of writing the chemical names of the elements. Symbols for the
elements usually consist of one or two letters. Some man-made elements have three letters
in their chemical symbols. If the chemical symbol is just one letter, that letter is a capital
letter. If the symbol has two or more letters, then the first letter is a capital and the
following letters are lower case. This standard for writing symbols for the elements makes
it easy for scientists to identify the specific elements.
In addition to having a chemical symbol, each element has an atomic number. The atomic
number is the number of protons in an atom’s nucleus. This number is also usually equal
to the number of electrons in the atom as well. The atomic number is a unique property
that identifies an element. No two elements have the same atomic number. Elements are
arranged on the Periodic Table according to their atomic number. Atomic numbers
increase as you read the elements from left to right.
Another important property of elements is atomic mass. Atomic mass is equal to the
number of protons and number of neutrons in an atom. Since electrons are so small, their
mass is not figured into the atomic mass. The atomic mass that appears on the periodic
table is the average mass of an element’s atoms. Atomic mass increases with atomic
number.
1.
Read, “Using the Periodic Table.”
2.
Reread the article and highlight important information about the elements and their
placement on the periodic table.
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Student Resource Sheet AC - 12
3.
What method do scientists use when coming up with chemical symbols?
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4.
Study the key in Figure 1, “Element Key.”
Figure 1: Element Key
Atomic
Number
8
O
Element
Name
5.
Atomic Mass
15.9994
Chemical Symbol
Oxygen
Use the key and the information from the text to complete Chart 1, “Elements of the
Periodic Table.”
Chart 1:
Elements of the Periodic Table
Element Name
Chemical Symbol
Atomic Number
Atomic Mass
Hydrogen
Na
17
Copper
4.00
6. Describe a pattern that exists between the atomic number and the atomic mass.
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If an atom has 15 protons, what conclusions can you make about the element’s atomic
number? What would this element be?
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7.
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Student Resource Sheet AC - 12
Activity 2: Chemical Patterns
8.
Study the element resource cards provided by your teacher.
9.
Find the elements that are gases at room temperature.

List the elements that are gases:
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
On which section of the periodic table are these elements located?
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10. Find all of the elements that have the words “silver” and “metal” in their description.

List the elements:
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
On which section of the periodic table are these elements located?
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11. Find all of the elements with 7 outer electrons.
 List the elements:
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 In what way are these elements grouped?
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12. Read, “It’s Elementary.”
Analysis
Describe how the properties of an element can be determined based upon the element’s
location on the periodic table. Use specific examples and evidence from the
investigation to support your response.
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1.
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Student Resource Sheet AC - 12
IT’S ELEMENTARY
All of the elements are organized on the Periodic Table of the Elements. At first glance,
the periodic table may not make much sense to you. However, knowing how to read the Periodic
Table of the Elements can provide you with important information about each element. On the
right side of the periodic table, you will notice a zigzag line (See Figure 1). This line is very
important in distinguishing among elements. All of the elements that are located to the left of
this zigzag line are considered to be metals. Elements that are to the right of the zigzag line are
considered to be nonmetals. Metals and nonmetals have very different properties. As a result,
metals and nonmetals will combine to form
Group
Figure 1
new substances.
In addition to the zigzag line, the
periodic table contains vertical columns of
elements as well as horizontal rows of
elements. The vertical columns are called
Period
groups. There are eighteen groups of
elements (See Figure 1). Within each group,
the elements have similar but not identical
properties. These properties are determined
by the valence electrons for an element’s atoms. Valence electrons are the outermost
electrons of an atom. The electrons are important because they are involved in the chemical
bonding of elements to make compounds. As a result, these electrons help to determine the
properties of the elements in a group. All of the elements in a given group have the same
number of valence electrons. For example all of the elements in Group 1 or IA have one
valence electron. This characteristic gives the elements in the family similar properties. In
general, all metals have 1, 2, or 3 valence electrons. Nonmetals will have 4, 5, 6, 7, or 8
valence electrons.
Lastly, there are seven horizontal rows or periods (See Figure 1) on the periodic table.
Unlike the elements in each family, the elements in each period do not share common
properties. The properties of the elements change dramatically across any given period.
However, there is still a pattern to the periods of elements. The first element in a period is
always an extremely active metal. The last element in a period is always an inactive gas. For
example, in period 3, sodium (Na) is an active metal while argon (Ar) is a stable, non-reactive
gas.
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