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Chapter 12
Section 1
Arranging the Elements
The Periodic Table
Crash Course --- The Periodic Table
Why arrange the elements?
• Read page 336
• Why would grouping elements by their
properties help scientist?
• So they could understand how the elements
interact with one another.
• What helped Mendeleev see the pattern of
the elements?
• He arranged them in order of increasing
atomic mass
Read p.337
• What was seen when Mendeleev arranged the
elements in order of increasing mass?
• He saw a repeating pattern
• What is the name of something that occurs or
repeats at regular intervals?
• Periodic
• Who worked with the atomic number (number of
protons) in atoms
• Henry Moseley
Properties p.340-341
Metals
WHERE
Outer layer of electrons
Describing words
Non-Metals
Metalloids
Metals
Nonmetals
Where:
To the left of the zigzag line Right of the zigzag line
Outmost electron layer:
Few electrons in their
outermost layer
Describing Words:
Shiny, ductile, good
convertors of electricity,
malleable, and conduct
thermal energy
Metalloids
Border the zigzag line
Almost complete set of
electrons in their
outermost layer
Almost half of a complete
set of electrons in their
outermost layer
Brittle and can shatter, not
shiny, poor conductors of
energy
Mostly shiny, can be brittle
or hard, can conduct
energy at high temps.
Decoding the periodic table
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Read p.342
What does a chemical symbol do?
Identify the element
How are chemical symbols written?
With a capital letter and a lower case letter for
the second letter if needed
• New elements are written how?
• With temporary 3 letter symbols
Periods
• What is a period in chemistry?
• A horizontal row of elements in the periodic
table
• The physical and chemical properties in these
rows follow what type of pattern?
• repeating
Columns
• What is a group?
• A vertical column of elements in the periodic
table; elements in a group share chemical
properties
• Why is a group sometimes called a family?
• Often, they have similar chemical and physical
properties
• Bozerman Science --- A Tour of the Periodic
Table
Exit Slip
• On a slip of paper, answer the following
questions:
• 1. How are the elements arranged in the
modern periodic table?
• 2. A horizontal row of elements in the periodic
table.
• 3. A column of elements is known as a family
or a __________.