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Periodic Table

Periodic Table. 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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Periodic Table

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

  12. “The elements were not being arranged to make a periodic table, but to fit the periodic table”

  13. 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 Meyer vs. Mendeleyev

  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. Today’s Table

  18. First Elements Discovered: Carbon Sulfur Copper Gold & Silver Iron Tin Antimony Mercury Lead Oxygen (1772) First Classified Groups: Gases Non-Metals Metals Earths More History

  19. 8A0 1A 2A 3A 4A 5A 6A 7A • The elements in the A groups are called the representative elements

  20. Transition metals • The Group B elements

  21. VIIIB IA IIA VIB VIIB IIIB IVB VB 1 1A 2 2A 8A 18 13 3A 14 4A 15 5A 16 6A 7A 17 VIIIA VIA VIIA IIIA IVA VA IB IIB 3 3B 4B 4 5 5B 6B 6 7 7B 8 8B 9 8B 10 8B 1B 11 2B 12 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. These are called the inner transition elements and they belong here The group B are called the transition elements

  27. Metals

  28. Metals & Their Properties • Metals are good conductors of heat and electricity • Metals are malleable • Metals have high luster

  29. 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

  30. Non-metals

  31. 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

  32. Example of Nonmetals • Sulfur was once known as Brimstone • Microspheres of phosphorus, a reactive nonmetal

  33. Metalloids or Semimetals • Properties of both • Semiconductors

  34. 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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