Periodic Table

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Periodic Table
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History

• Antoine Lavoisier Father of Modern Chemistry
• 1829 German J. W. Dobereiner Grouped elements
  into triads
• Three elements with similar properties
• Properties followed a pattern
• The same element was in the middle of all trends
• Not all elements had triads

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Law of Octaves

• 1862 John Newlands developed Law of Octaves
• The elements showed a repetition in their
  chemical properties after 8 elements
• Used Atomic Weights but not actual values
• Important because showed the first pattern of
  repeating properties

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Julius Lothar Meyer

• Meyer first table published 1864 containing 28
  elements
• Arranged in order of Atomic Weight and made a
  clear horizontal relationship between Atomic
  Weight and Atomic Volume
• Allowed physical properties to outweigh chemical
  properties
• Anticipated Mendeleev by years

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Meyer

• Left gaps to denote unknown elements
• Not willing to make predicitions
• More focused on Physical properties not chemical
  properties
• Bitter battle with Mendeleev
• Lost to Mendeleev because of Mendeleevs forceful
  ways

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Dmitri Mendeleev

• Mendeleev was known as the Father of the
  Periodic Table
• DOB 1834-1907
• Created the first table on 3-1-1869
• Table had 70 elements
• Used properties to set up table

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History

• Russian scientist Dmitri Mendeleev taught
  chemistry in terms of properties
• Mid 1800 atomic masses of elements were known
• Wrote down the elements in order of increasing
  mass
• Found a pattern of repeating properties
• Not first to develop system but his version had
  the strongest impact

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Mendeleevs Table

• Grouped elements in columns by similar properties
  in order of increasing atomic mass
• Found some inconsistencies - felt that the
  properties were more important than the mass, so
  switched order.
• Found some gaps
• Must be undiscovered elements
• Predicted their properties before they were found

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Mendeleev

• Distinguished from competitors by a devotion to,
  and love for, the individuality of the elements
  that went hand in hand with an intimate knowledge
  of their chemical characteristics
• Focused on both physical and chemical properties

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Mendeleyev Cont.

• Chemical Properties Used
• Atomic Weight vs. Valancey
• He could only predict these properties
• His work preceded chemical advances by 30 years
• Produced his table 27 years before the first
  subatomic particle, the electron was discovered
• Did not predict Noble Gases

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Acceptance

• Mendeleevs table received real acceptance in
  1875
• Discovery of Scandium, Germanium and Gallium
  showed Mendeleevs predictions were correct.

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The elements were not being arranged to make a
periodic table, but to fit the periodic table
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Meyer vs. Mendeleyev

• Julius Meyer (1830-1895)
• Created a table that plotted
• Atomic Volume vs. Atomic Weight
• Lost out to Mendeleev

• Published before Meyer
• Final Table
• Atomic Weight vs. Valency
• Table had 8 columns but was missing Noble Gases
• Discovered 30 years later

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Modern Russian Table
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Spiral Periodic Table
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Changing of Table

• Henry Moseley (1887-1915) changed table in 1913
  by increasing atomic number
• Biggest Impact
• Glenn Seaborg rare earth series from Actinium
  (89) up.
• Current Table Used Today
• Minor Changes inner transitional Lu Lr
  replaced La Ac
• Bohr first linked Quantum Theory

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Todays Table
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More History

• First Elements Discovered
• Carbon
• Sulfur
• Copper
• Gold Silver
• Iron
• Tin
• Antimony
• Mercury
• Lead
• Oxygen (1772)

• First Classified Groups
• Gases
• Non-Metals
• Metals
• Earths

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The Modern Periodic Table

• Our current periodic table shows elements in
  order of increasing atomic number (protons)
• Elements in the same column have similar
  properties, and are called a group or family.
  Groups are designated in two ways
• A Roman numeral (I through VIII) and a letter (A
  or B)
• An Arabic number (1-18)
• A horizontal row of elements is a period.
  Elements in the same period have properties that
  tend to vary in a regular fashion. Periods are
  designated by an Arabic number (1-7).

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Vertical Columns

• Known as Groups or a Family
• Elements in same group have similar physical
  chemical properties
• Each group is identified by a group number and
  group letter

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Groups and Periods
Figure 2.19
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Similar Properties in Groups

• Potassium metal reacts violently with water to
  producing a basic solution and flammable hydrogen
  gas.
• All alkali metals react with water to produce
  hydrogen gas.

Figure 2.21
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Classification of Elements

• Groups
• IA Alkali metals
• IIA Alkaline Earth Metals
• VIIA Halogens
• VIIIA Noble Gases
• Periods
• Metals, Nonmetals, Metalloids
• Main-group Elements, Transition Metals, and
  Inner-transition Metals.

Figure from p. 73
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Main-Group Elements and Transition Metals

• Main-group elements (also called representative
  elements) contain any element in the eight groups
  designated with the letter A. (In the Arabic
  numbering, groups 1, 2, and 13-18)
• Transition metals contain any element in the 10
  groups designated with the letter B. (In the
  Arabic numbering, groups 3-12)
• Inner-transition metals contain the lanthanides
  and actinides listed separately at the bottom of
  the table.

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Common Group Names

• Some groups have descriptive names that are
  commonly used instead of their group numbers.
• Alkali metals
• Group 1 (IA) metals (hydrogen is a nonmetal)
• are considered reactive because the react readily
  with other elements and compounds
• Alkaline earth metals
• Group 2 (IIA) metals
• are more reactive than the transition metals but
  less reactive than alkali metals

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Common Group Names

• Some groups have descriptive names that are
  commonly used instead of their group numbers.
• Halogens
• Group 17 (VIIA) nonmetals
• exist naturally as diatomic molecules
• Noble gases
• Group 18 (VIIIA) nonmetals
• are also called inert gases
• are so named because they do not chemically react
  with other elements (with the exception of
  krypton and xenon)

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• The elements in the A groups are called the
  representative elements

8A0
1A
2A
3A
4A
5A
6A
7A
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Transition metals

• The Group B elements

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Other Systems
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• Horizontal rows are called periods
• There are 7 periods

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• Group 1A are the alkali metals
• Group 2A are the alkaline earth metals

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• Group 7A is called the Halogens
• Group 8 are the noble gases

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• The group B are called the transition elements

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Metals, Nonmetals, and Metalloids

• The periodic table has many classifications.
  Groups and periods are one classification.
  Another classification denotes metals, nonmetals,
  and metalloids.
• A stair-step line starting at boron (B) separates
  metals (to the left of the line) from nonmetals
  (to the right of the line).
• The metalloids exist along the line.
• Metalloids are elements that have physical
  properties resembling a metal, but the chemical
  reactivity of a nonmetal.

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Metals
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Metals Their Properties

• Metals are good conductors of heat and
  electricity
• Metals are malleable
• Metals have high luster

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Example of Metals

• Copper is a relatively soft metal and a very good
  electrical conductor
• Mercury is the only metal that exists as a liquid
  at room temperature

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Non-metals
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Nonmetals Their Properties

• Carbon, the graphite in a pencil is an example of
  a nonmetallic elements
• Nonmetals are poor conductors of electricity
• Can be brittle
• Non-lustrous
• Many are gases at room temperature

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Example of Nonmetals

• Sulfur was once known as Brimstone
• Microspheres of phosphorus, a reactive nonmetal

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Metalloids or Semimetals

• Properties of both
• Semiconductors

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Example of a Metalloid

• Silicon is a metalloid
• Silicon is brittle like a nonmetal
• Silicon has metallic luster
• Silicon is a semiconductor of electricity

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Metals, Nonmetals, and Metalloids
Figure 2.20
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Modern Periodic Table

• Elements are divided into two main classes

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Modern Periodic Table

• Except for hydrogen, those elements to the left
  of the line are metals

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Modern Periodic Table

• Elements to the right of the line are nonmetals

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Modern Periodic Table

• Elements around the line are referred to as
  metalloids

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