Chapter 3 Chemistry

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Chapter 3 Chemistry

• The development of the periodic table.

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Organizing the elements

• By 1860, 60 elements had been discovered.
• However, there was no organization to them.
• Scientists did know that certain elements behaved
  similarly.

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Doberiener

• In 1829, J.W. Doberiener started to group
  elements into threes called triads.
• These triads had similar characteristics and
  properties.
• There was also an orderly pattern with the triads
  as Table 3.1 pg 87 suggests.

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Mendeleev

• In 1869, Mendeleev started to make a table by
  organizing the elements by increasing mass.
• He also started a new column when elements had
  similar properties.
• These similar properties had to do with the
  valence electrons.

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Periodicity

• The periodic table had periodicity or a repeating
  pattern.
• However, there were some missing elements and he
  called them eka-aluminum.
• Those that were missing, he predicted the mass
  and characteristics of them.

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Periodic law

• Periodic law is when physical and chemical
  properties repeat in a regular pattern when they
  are arranged in the order of increasing atomic
  number.
• With this, we have our modern periodic table.

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Periodic Table Video
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Periodic Table

• Periods- horizontal rows on the periodic table.
• Group- also called families, these are the
  vertical rows of the periodic table.
• Periods have to do with the energy levels.
• Groups have to do with the valence electrons.
  Except transition metals.

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Four Common Names

• Group 1 are the alkali metals
• Group 2 are the alkali earth metal
• Group 17 are the halogens (salt formers)
• Group 18 are the noble gases.

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Metals, non-metals, metalloid

• Metals are to the left of the stair step.
• Non-metals are to the right of the stair step.
• Metalloids touch the stair step.

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Metals

• Metals will have luster, conduct heat and
  electricity and will bend without breaking.
• They will also lose their electrons fairly easily.

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Transition Metals

• Groups 3 through 12 are called transition metals
  or elements.
• These metals are not as predictable as the other
  elelments.

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Actinides and Lanthanides

• These series are separated for if they were left
  in, the table would be out of proportion and
  would be too long.
• Lanthanides are rare earth metals for they are
  not found very often.
• Actinides are radioactive and beyond 92 are all
  synthetic or man made.

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Nonmetals

• Nonmetals are to the right of the stair step.
• They do not conduct electricity, poor conductors
  of heat and brittle when solid.
• They lack luster and have very low boiling points.

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Metalloids

• These lie along the stair step.
• The have the properties of both a metal and
  non-metal.
• Some of the metalloids can be a semi-conductor in
  which it can conduct a little bit of electricity
  but will not heat up.

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Histroy of the semi-conductor
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Making of the semiconductor
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General Properties

• Read Pages 106 and 107

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Nitinol

• Nitinol is an alloy of nickel and titanium.
• Its properties can serve many uses.
• http//www.metacafe.com/watch/1040775/muscle_wire_
  nitinol/

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Electrical Conduction

• Silicon has four valence electrons and are held
  in a crystal structure.
• Adding a five electron element (such as
  phosphorous) will allow an extra electron to
  conduct electricity.
• This is an n-type because electrically charged
  particles will conduct electricity.

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Electrical Conduction

• Silicon has 4 valence electrons, by adding boron
  which has three valence electrons a hole is
  created.
• There is a movement of positive charged particles
  in the atom to produce electricity.
• This is called a p-type.

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Diodes

• Diodes are the combination of n and p type
  semiconductors.
• Transistors are made up of diodes and transistors
  are used to increase the strength of electricity