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Periodic Table History. History of the Periodic Table: At the conclusion of our time together, you should be able to:. List one of the earliest contributors to thediscovery of the elements Explain triads and who developed this table of the elements - PowerPoint PPT Presentation
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Periodic Table History
History of the Periodic Table:At the conclusion of our time together, you should be able to:1. List one of the earliest contributors to
the discovery of the elements2. Explain triads and who developed this
table of the elements3. Explain the law of octaves and who
developed this table of the elements4. Explain the first real periodic table and
who developed this table of the elements
5. Mark a period, group, and the metal, nonmetal, metalloid areas of the periodic
table
Aristotle
4 Elements
Fire, Water, Air, Earth
~350 B.C.-
14 elements were known
By 1700 -
Antoine Lavoisier wrote the first extensive list of 33 elements.
~1789-
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.
1829 -
Cl, Br, ICa, Sr , BaS, Se, TeLi, Na, K
Other Triads of Dobereiner:
Little Known Phobias!
Baabaaphobia
Fear of being fleeced
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 FNa Mg Al Si P S Cl
1864 -
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!
1869 -
He left blanks where elements seemed to be missing.
There were places where heavier elements were put before lighter elements because of their properties:
Te – I Co – NiAr – K
(He felt the mistake was in measuring the mass and this would be corrected with further research.)
Mendeleev (cont.)
The Periodic Table
Dmitri Mendeleev (1834 - 1907)
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.”
1913 -
Murphy's Lawsof
Science and Technology
Technology is dominated by those who manage what they do not understand.
Glenn Seaborg(1912-1999)
Discovered 8 new elements.
Only living person for whom an element was named.
The Language of ChemistryThe elements, their
names, and symbols are given on the PERIODIC TABLE
How many elements are there?• 117 elements have been identified• 90 elements occur naturally on Earth
• Examples: gold, aluminum, lead, oxygen, carbon• 27 elements have been created by scientists
• Examples: technetium, americium, seaborgium
Periodic Table Terminology
Period/Series = horizontal rows
Group/Family = vertical columns
MetalsLocated to the left of the staircase lineCharacteristics
Lose electrons to form + ions (cations)ShinyMalleableDuctileGood conductors of heat & electricityReact with acid
Most metallic element = Fr (francium)
NonmetalsLocated to the right of the staircase lineCharacteristics:
Tend to gain electrons to form – ions (anions)
DullPoor conductors of heat and electricityBrittle
Most reactive nonmetal = F (fluorine)
Metalloids
Located on and below the staircase line except At, Po and Al.
Characteristics:Tend to gain or lose electronsShiny and dullGood and poor conductors of heat and
electricityMalleable and brittle
History of the Periodic Table:Let’s see if you can:
1. List one of the earliest contributors to discovery of the elements
2. Explain triads and who developed this table of the elements
3. Explain the law of octaves and who developed this table of the elements
4. Explain the first real periodic table and who developed this table of the elements
5. Mark a period, group, and the metal, nonmetal, metalloid areas of the periodic
table
Where are Periods, Groups, Metals, Nonmetals, and Metalloids?
1. List one of the earliest contributors to discovery of the elements
2. Explain triads and who developed this table of the elements
3. Explain the law of octaves and who developed this table of the elements
4. Explain the first real periodic table and who developed this table of the elements
Toburen’s Attempt at a Periodic Table: