The Periodic Table
Unit II—Part 4
Adapted by NCDPI – Unit 2 Matter all around us
The Father of the Periodic Table—
Dimitri Mendeleev
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Mendeleev was the first scientist to notice
the relationship between the elements
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Arranged his periodic table by atomic mass
Said properties of unknown elements could be
predicted by the properties of elements around
the missing element
Image taken from:
http://jscms.jrn.columbia.edu/cns/2006-04-18/fidoluxuriantflowinghair/mendeleev
Henry Moseley
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Moseley later discovered that the
periodic nature of the elements was
associated with atomic number, not
atomic mass
Image taken from:
http://dewey.library.upenn.edu/sceti/smith/
The Periodic Table
Column = Group or
Family
18 columns on the
Periodic Table
Row = Period
7 rows on the
Periodic Table
Periods
•Each row is called a “period”
•The elements in each period have
the same number of energy levels
1st Period = 1 E. Level
2nd Period = 2 E. Levels
3rd Period = 3 E. Levels
4th Period = 4 E. Levels
5th Period = 5 E. Levels
6th Period = 6 E. Levels
7th Period = 7 E. Levels
Middle School Science
Image: Chem4kids.com
Groups
•Each column is called a “group”
•Each element in a group has the same number of electrons
in their outermost energy level (valence electrons)
Except for He, it
has 2 electrons
Group 1 = 1 electron
Group 2 = 2 electrons
4
Group 8 =
8 electrons
Middle School Science Image: Chem4kids.com
Metals, Nonmetals, and
Only
Semi-metals
Nonmetals are on the
nonmetal on the
metal side
Metals are to the
left of the
stair- step
Semi-metals,
“metalloids,”
touch the
stair-step
right of the stair-step
Special Rows on the PT
Lanthanides
Actinides
What does the information in the
box tell me?
Atomic Number =
# of protons
Atomic Mass =
# of protons
plus neutrons
1
H
1.008
Elemental
Symbol
The Groups of the Periodic Table
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Group 1: The Alkali Metals
Most reactive metals on the PT
Rarely found free in nature
Charge of 1—1 valence electron
1
H
1.008
3
Li
6.941
11
Na
22.990
19
-
K
-
39.098
-
37
-
Rb
+
+++++++
++ +
-
-
85.468
-
Cs
-
-
55
132.905
-
87
Fr
(223)
The Groups of the Periodic
Table
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Group 2: The Alkaline Earth Metals
Still quite reactive
 Charge of 2—2 valence electrons
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Image: Chem4kids.com
Image: http://wildeboer-fitch.wikispaces.com/2008fall+Calcium
T he Groups of the Periodic Table
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Groups 3-12: Transition Metals
Found freely and in compounds in nature
 Charge is usually 2 but can vary—usually 2
valence electrons
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Group 13: Boron Family
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Charge is 3—3 valence electrons
https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTOt9q27_Eou8z7JNLK7Q33g1oW5nLuZ468bup9AzxryqyuAaV_dA
The Groups of the Periodic Table
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Group 14: The Carbon Family
Contains elements that can form unusual
bonds (carbon and silicon)
 Charge is +4 or -4—contains 4 valence
electrons
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Group 15: The Nitrogen Family
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Charge is -3—contains 5 valence electrons
The Groups of the Periodic Table
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Group 16: The Oxygen Family
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Group 17: The Halogens
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Also known as the chalcogens
Charge is -2 has 6 valence electrons
Most reactive nonmetals
charge is -1 has 7 valence electrons
Group 18: The Noble Gases (The Inert Gases)
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Nonreactive
Charge is 0—2 or 8 valence electrons
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https://www.google.come/search?q=valence+electrons+periodic+table
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