1. Periodic Table History

2. History of the Periodic Table: At the conclusion of our time together, you should be able to:
List one of the earliest contributors to discovery of the elements
Explain triads and who developed this table of the elements
Explain the law of octaves and who developed this table of the elements
Explain the first real periodic table and who developed this table of the elements
Show a period, group, and the metal, nonmetal, metalloid areas of the periodic table

3. Aristotle 4 Elements Fire, Water, Air, Earth
~350 B.C.-
Aristotle 4 Elements Fire, Water, Air, Earth

4. By
14 elements were known

5. Antoine Lavoisier wrote the first extensive list of 33 elements.
~1789-
Antoine Lavoisier wrote the first extensive list of 33 elements.

6. 1829 -
Johann Dobereiner (German Chemist) noticed that Br, Cl, and I had similar properties and that Br’s atomic mass was between that of Cl & I. He found three other groups with similarities. He called these groups triads.

7. Other Triads of Dobereiner:
Cl, Br, I
Ca, Sr , Ba
S, Se, Te
Li, Na, K

8. 1864 -
John Newlands (English Chemist) arranged the now known 62 elements from lightest to heaviest. He also noticed that every 8th element had similar chemical and physical properties. Their properties were repeating. This became known as Newland’s Law of Octaves. Li Be B C N O F Na Mg Al Si P S Cl

9. 1869 -
Dmitri Mendeleev (Russian Chemist) organized the elements by atomic mass also but made it into table form to help his students. Elements with similar properties were put into the same column. Considered the Father of the Modern Period Table!

10. Mendeleev (cont.) He left blanks where elements seemed to be missing.
There were places where heavier elements were put before lighter elements because of properties:
Te – I Co – Ni Ar – K
He felt the mistake was in measuring the mass and this would be corrected with further research.

11. The Periodic Table
Dmitri Mendeleev ( )

12. Mendeleev (cont.)
This gave rise to the Periodic Law, “Properties of elements are periodic functions of their atomic mass.”

13. 1913 -
Henry Moseley (English Chemist) arranged elements by atomic number. This gave rise to a New Periodic Law, “Properties of elements are periodic functions of their atomic number.”

14. Glenn Seaborg (1912-1999) Discovered 8 new elements.
Only living person for whom an element was named.

15. The Language of Chemistry
The elements, their names, and symbols are given on the PERIODIC TABLE
How many elements are there?
117 elements have been identified
82 elements occur naturally on Earth
Examples: gold, aluminum, lead, oxygen, carbon
35 elements have been created by scientists
Examples: technetium, americium, seaborgium

16. Periodic Table Terminology
Periods/Series = horizontal rows 
Group/Family = vertical columns

18. Metals Located to the left of the staircase line Characteristics
Lose electrons to form + ions (cations)
Shiny
Malleable
Ductile
Good conductors of heat & electricity
React with acid
Most metallic element = Fr (francium)

19. Nonmetals Located to the right of the staircase line Characteristics:
Tend to gain electrons to form – ions (anions)
Dull
Poor conductors of heat and electricity
Good insulators
Brittle
Most reactive nonmetal = F (fluorine)

20. Metalloids Located on and below the staircase line except At and Al.
Characteristics:
Tend to gain or lose electrons
Shiny and dull
Good and poor conductors of heat and electricity
Malleable and brittle

21. Solids, Liquids and Gases at Room Temp

22. History of the Periodic Table: Let’s see if you can:
List one of the earliest contributors to discovery of the elements
Explain triads and who developed this table of the elements
Explain the law of octaves and who developed this table of the elements
Explain the first real periodic table and who developed this table of the elements
Show a period, group, and the metal, nonmetal, metalloid areas of the periodic table