Chapter 5 The Periodic Table

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Chapter 5 The Periodic Table
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5.1 Organizing the Elements

• Dmitri Mendeleev 1860s
• Russian chemist and teacher
• Used the game of solitaire as a model
• Made a deck of cards of the elements listing
  the elements name, mass and properties
• Arranged the elements into rows of increasing
  mass so that elements with similar properties
  were in the same column

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• Periodic Table
• An arrangement of elements in columns based on a
  set of properties that repeat from row to row
• Mendeleev was able to predict the properties of
  elements that had not yet been discovered. This
  showed how useful the periodic table could be.

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Mendeleevs Table
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5.2 The Modern Periodic Table

• In the modern periodic table, elements are
  arranged by increasing atomic number ( of P)
• Periods horizontal rows elements in the same
  period have the same number of energy levels

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• Groups (Families) vertical columns elements in
  the same group have similar properties because
  they have similar electron configurations they
  have the same number of valence electrons
• Valence electrons electrons in the outermost
  energy level of an atom

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• Atomic Mass value that depends on the
  distribution of an elements isotopes in nature
  and the masses of those isotopes
• Atomic Mass Units (amu) 1/12 the mass of a
  carbon-12 atom

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• Atomic Mass is based on the weighted average mass
  of all the isotopes of an element.
• For example
• The atomic mass of chlorine is 35.453 because
  Cl-35 is more common than Cl-37.

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Classes of Elements

• Metals
• Majority of elements are metals
• Left side of periodic table
• Good conductors of heat and electricity
• Malleable
• Ductile

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• Nonmetals
• Poor conductors of heat and electricity
• Low boiling points (many are gases at room temp.)
• Solids tend to be brittle

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• Metalloids (semiconductors)
• Properties that fall in between metals and
  nonmetals
• Metalloids ability to conduct heat and
  electricity depends on temp.
• Elements properties become less metallic and more
  nonmetallic as you move from left to right across
  a period.

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5.3 Representative Groups

• The Alkali Metals
• Group 1A
• 1 valence e-
• So reactive they are
• only found in nature as
• compounds
• Reactivity increases from
• top to bottom of group

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• Alkaline Earth Metals
• Group 2A
• 2 valence electrons
• Very reactive but less
• reactive than Group 1A
• Differences In the way
• they react with water

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Boron Family

• 3 valence e-
• Contains 1 metalloid
• and 4 metals
• Al is the most abundant
• metal in earths crust

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Carbon Family

• 4 valence e-
• Contains a nonmetal,
• 2 metalloids, and 2 metals
• Metallic nature of elements
• increases from top to bottom
• Most compound in the body
• contain carbon

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Nitrogen Family

• 5 valence e-
• 2 metalloids, 1 metal, 2 nonmetals
• N and P are found in fertilizers

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Oxygen Family

• 6 valence e-
• 3 nonmetals, 2 metalloids
• Oxygen is the most abundant ELEMENT in Earths
  crust

The picture above is Sulfur
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Halogen Family

• 7 valence e-
• Highly reactive nonmetals
• Fluorine most reactive halogen

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Noble Gas Family

• 8 valence e-
• All nonmetals
• Colorless, odorless gases
• Nonreactive (inert)