1. Unit II—Part 4 Adapted by NCDPI – Unit 2 Matter all around us
The Periodic Table
Unit II—Part 4
Adapted by NCDPI – Unit 2 Matter all around us

2. The Father of the Periodic Table—Dimitri Mendeleev
Mendeleev was the first scientist to notice the relationship between the elements
Arranged his periodic table by atomic mass
Said properties of unknown elements could be predicted by the properties of elements around the missing element
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3. Henry Moseley
Moseley later discovered that the periodic nature of the elements was associated with atomic number, not atomic mass
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4. The Periodic Table Column = Group or Family
18 columns on the Periodic Table
Row = Period
7 rows on the Periodic Table

5. 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
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6. 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
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7. Metals, Nonmetals, and Semi-metals
Only
nonmetal on the metal side
Nonmetals are on the right of the stair-step
Metals are to the left of the stair- step
Semi-metals,
“metalloids,”
touch the stair-step

8. Special Rows on the PT
Lanthanides
Actinides

9. What does the information in the box tell me?1 H
1.008
Atomic Number = # of protons
Elemental Symbol
Atomic Mass = # of protons plus neutrons

10. The Groups of the Periodic Table
Group 1: The Alkali Metals
Most reactive metals on the PT
Rarely found free in nature
Charge of 1—1 valence electron 87 Fr
(223) 55 Cs 37 Rb
85.468 19 K
39.098 11 Na
22.990 3 Li
6.941 1 H
1.008 + -

11. The Groups of the Periodic Table
Group 2: The Alkaline Earth Metals
Still quite reactive
Charge of 2—2 valence electrons
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12. T he Groups of the Periodic Table
Groups 3-12: Transition Metals
Found freely and in compounds in nature
Charge is usually 2 but can vary—usually 2 valence electrons
Group 13: Boron Family
Charge is 3—3 valence electrons

13. The Groups of the Periodic Table
Group 14: The Carbon Family
Contains elements that can form unusual bonds (carbon and silicon)
Charge is +4 or -4—contains 4 valence electrons
Group 15: The Nitrogen Family
Charge is -3—contains 5 valence electrons

14. The Groups of the Periodic Table
Group 16: The Oxygen Family
Also known as the chalcogens
Charge is -2 has 6 valence electrons
Group 17: The Halogens
Most reactive nonmetals
charge is -1 has 7 valence electrons
Group 18: The Noble Gases (The Inert Gases)
Nonreactive
Charge is 0—2 or 8 valence electrons