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The Periodic Table
Guide Answer
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7A The Periodic Table
What is the periodic table and how many elements are there?
Virtually all the matter you see is made up of combinations of elements.
Scientists know of 118 different elements, of which about 90 occur naturally.
Each element has its own unique kind of atom. The periodic table is a chart
that shows all of the elements in order of increasing atomic number.
A
Elements and the atomic number
B
Building the periodic table
Materials
• Periodic table tiles
Every element is given a symbol of one or two letters. For example, the symbol for hydrogen is
a capital letter H. The symbol for lithium is two letters, Li. Each element also has a unique
number called the atomic number. The atomic number is the number of protons in the nucleus
of all atoms of that element. Atomic number one is the element hydrogen. Hydrogen is the
lightest element known, since it only has one proton in the nucleus. Atomic number 92 is the
element uranium which is one of the heaviest elements that occurs in nature. Uranium has 92
protons in its nucleus.
For this part of the investigation you are going to build the entire periodic table of elements.
The table has a very specific shape which corresponds to the chemical properties of the
elements. All of the elements fill-in this shape in order of their atomic number starting from
the upper left-hand corner. As you build the table, be sure to follow the diagram below to get
the right shape. Some of the squares have the atomic numbers of the elements shown to help
you get the shape correct.
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Ca.
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thinkTable of Contents Teacher's Guide Answer Sheet Back
Many printed periodic tables look like the diagram on the
right instead of having the shape that you built. Can you
think of a reason why?
Sections of the periodic table
D
The periodic table is organized into 11 sections (shown as a-k). Each section contains elements
with similar chemical properties. Most sections are single columns. One section includes many
columns and two sections are parts of entire rows.
a.
Locate the element that is the first one in each of the following sections.
b.
Research the name (if any) of this section.
c.
Research any properties that elements from this section share.
Table 1: Sections of the Periodic Table
Diagram
First element
(name)
Section name
(if any)
Representative chemical properties
a
b
c
d
e
f
g
h
i
j
k
E
Applying what you have learned
a.
Each row of the periodic table contains only a certain number of elements. What does this
have to do with the structure of the atom? Research this question in your textbook.
b.
Which section of the periodic table above contains the element argon? What
characteristic do the elements in this section share?
c.
Which sections contains the element carbon? What characteristic do these elements
share?
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