Periodic Table

1
Periodic Table
2
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

3
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

4
Julius Lothar Meyer

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

5
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

6
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

7
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

8
Dmitri Mendeleyev

• Mendeleyev 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

9
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

10
Mendeleyev Cont.

• Properties Used
• Atomic Weight
• Melting Pts.
• Densites
• 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

11
Acceptance

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

12
The elements were not being arranged to make a
periodic table, but to fit the periodic table
13
Meyer vs. Mendeleyev

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

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

14
Modern Russian Table
15
Spiral Periodic Table
16
Changing of Table

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

17
Todays Table
18
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

19

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

8A0
1A
2A
3A
4A
5A
6A
7A
20
Transition metals

• The Group B elements

21
Other Systems
22
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

23

• Horizontal rows are called periods
• There are 7 periods

24

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

25

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

26

• The group B are called the transition elements

27
(No Transcript)
28
Metals
29
Metals Their Properties

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

30
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

31
Non-metals
32
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

33
Example of Nonmetals

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

34
Metalloids or Semimetals

• Properties of both
• Semiconductors

35
Example of a Metalloid

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