From Chaos to Order

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Periodic Table
From Chaos to Order
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Empedocles (440 B.C.)
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Democritus Athens, Greece 400 B.C.
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The smallest particles of matter are indivisible.
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Since atomos is the Greek word for indivisible
I shall call these particles atoms.
Atoms cannot be destroyed, so there is
conservation of matter.
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Aristotle Athens, Greece 340
B.C.
Aristotle studied under Plato and disagreed with
Democritus. However, Aristotle had the most
influence on the history of chemistry.
Besides chemistry, he also tackled physics,
biology, psychology, and logic.
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Aristotles Table of the Elements
Dry
Hot
Cold
Wet
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Antoine Laurent Lavoisier France
1793

• Lavoisier has been called the father of modern
  chemistry.

• Started a system of chemical nomenclature that
  used ide, -ic -ous endings.

Examples Sodium chloride, Ferric oxide and
Ferrous oxide
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Lavoisiers Traite Elementaire de Chimie (33)
Metals Antimony Arsenic Bismuth Cobalt
Copper Gold Iron Lead Manganese Mercury
Molybdena Nickel Platina Silver Tin
Tungstein Zinc
Based on their chemical properties
Nonmetals Sulphur Phosphorus Charcoal Muriatic
radical Fluoric radical Boracic radical
Gases Light Heat Oxygen Azote Hydrogen
Earths Chalk Magnesia Barote Alumine Silice
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John Dalton England
1796

• Created the 1st Atomic Theory
• - All matter was composed of small indivisible
  particles called atoms
• Atoms of given element possess unique
  characteristics and weight
• - Three types of atoms exist simple (elements),
  compound (simple molecules), and complex (complex
  molecules)

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Arranged from light to heavy by their relative
weights
Daltons Symbols
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Each symbol represented one atom and the formula
of a compound was made up of the symbols of its
elements, it showed how many of these atoms were
present in the molecule.
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Johan Jacob Berzelius from Sweden
He found Daltons symbols difficult.
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Berzelius Symbols for Elements

• I will use the initial letter.
• If two initials are the same, I will use the
  first two letters.
• If the first two letter are the same, I will use
  the initial letter and the 1st consonant.
• Older elements take the symbol from their Latin
  name.
• Fe comes from ferrum not iron.
• Instead of G for gold he wants Au from aurum.
• Instead of S for Silver he wants Ag from
  argentum.
• Newer symbols come from English names.
• O comes from oxygen.

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By 1830, fifty-five different elements were
recognized. The number became too great for the
comfort of chemists. The elements varied widely
in properties and there seemed little order about
them. Why were there so many? And how many
more yet remained to be found? It was tempting
to search for order in the list of elements
already known. Perhaps in this manner some reason
for the number of elements might be found and
some way of accounting for the variation of
properties that existed.
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John Newlands England
1867
Researchers had already began to arrange and
classify elements - Metals vs. non-metals -
In tables of increasing atomic weight
John Newlands had a different way to arrange
elements.
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He noticed that certain elements resembled one
another in behavior.

• Chlorine, bromine iodine
• violently corrosive
• form acids
• Lithium, sodium, potassium
• Unite violently with oxygen or water
• Oxides form caustic aqueous solutions

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Every eighth element has similar characteristics
Li Be B C N O F Na Mg
Al Si P S Cl K Ca ? ?
As Se Br
I call this the Law of Octaves
When I presented this theory to the England
Chemical Society and I was laughed at.
They said to arrange it alphabetically.
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Dmitri Ivanovich Mendeleev Russia
1871
Periodic Law
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Like Newlands, he used the lithium, sodium, and
potassium plus the chlorine family as guide posts
He also saw a periodic repeating of
characteristics.
Li Be B C N O F Na Mg
Al Si P S Cl K Ca ? ?
As Se Br
However on his 3rd row, he thought there were
more than the seven elements than Newland had
listed.
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There was a problem with Mendeleev's table! If
the elements were arranged according to
increasing atomic masses, Tellurium and Iodine
seemed to be in the wrong columns. Their
properties were different from those of other
elements in the same column
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Henry Gwyn Jeffreys Moseley England 1913
Periodic Law Revised
He stated that physical and chemical properties
are a periodic function of their atomic number,
rather than mass. This better explained the gaps
in the table.
Atomic number protons Herewith he created
the modern periodic table in which each
succeeding element has one more proton and
electron than the former element.
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From Chaos to Order
The elements are ordered by the number of protons
they have in their nucleus.
Atomic Number
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From Chaos to Order
The elements are listed by increasing mass, BUT
groups by reoccurring properties.
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End