Periodic Table

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Periodic Table

• Applied Chemistry
• Chapter 3

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History

• Dmitri Mendeleev developed a periodic table in
  1869 by arranging the elements in order of
  increasing atomic mass.

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Modern Periodic Table

• Henry Moseley developed the modern periodic
  table, which arranges elements in order of
  increasing atomic number.

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Does it matter?

• Take a look at your periodic table. Find
  elements that would not have been in the same
  spot on Mendeleevs table.
• Ar and K, Co and Ni, Te and I, Th and Pa, U and
  Np, Pu and Am
• So, it is important to remember that the modern
  periodic table is arranged according to atomic
  number, and NOT atomic mass.

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Periodic Law

• The chemical and physical properties of the
  elements are periodic functions of their atomic
  number

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Groups

• Vertical columns of elements on the table are
  called groups or families.
• Elements in the same group have the same number
  of valence electrons, and therefore, similar
  properties.
• Groups 1,2, and 13-18 are called the
  representative elements.
• Groups 3-12 are the transition elements.

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Group names

• Group 1 contains the alkali metals.
• Notice that hydrogen is separate from the rest of
  the group. This is because hydrogen is NOT an
  alkali metal.
• Alkali metals are the most active metals, and
  Francium is the most active metal.
• Alkali metals are so active that they are not
  found free in nature.

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Group names

• Group 2 elements are the alkaline earth metals.
  They are very active, but not as active as group
  1 elements.
• Groups 3-12 are the transition elements. They
  can form colored solutions when dissolved in
  water.
• Groups13-16 are named according to the top
  element in the group. So, group 13 is the Boron
  family, 14 the Carbon family, and so on.

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Group names

• Group 17 contains the halogens. They are the
  most active nonmetals. Fluorine is the most
  active nonmetal. Group 17 is the only group that
  contains a solid, liquid and a gas at STP.
• Group 18 contains the noble gases. They are
  unreactive nonmetals.

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Periods

• There are 7 periods, or horizontal rows on the
  periodic table.
• Elements in the same period do NOT have similar
  properties. The properties change in a
  systematic way as you read across a period.
• Elements in the same period contain the same
  number of principal energy levels of electrons.

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Two rows at the bottom of the table

• The first row at the bottom is called the
  lanthanide series.
• The second row is called the actinide series.
  All actinides are radioactive.
• These elements have been placed at the bottom to
  condense the table. They really belong in the
  middle of the table.

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Metals, Nonmetals,and Metalloids

• Metals are located on the left side of the table.
  Groups 1-12 contain only metals (remember,
  hydrogen is not really in group 1)
• There is a zigzag or step line on the periodic
  table. All elements that have one full side
  touching this line are metalloids, EXCEPT
  ALUMINUM. There are 8 metalloids.
• Nonmetals are located on the right side of the
  table, with the exception of hydrogen. There are
  17 nonmetals.

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Properties of metals

• Metals are malleable, meaning they can be
  hammered into thin sheets (ex Aluminum foil)
• Metals are ductile, meaning they are able to be
  drawn into thin wire (ex Copper wire)
• Metals have high melting points
• Metals are good conductors of heat and
  electricity
• Metals have luster, or shininess

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Properties of nonmetals

• Nonmetals are brittle, meaning they break easily
• Nonmetals have low melting points
• Nonmetals do not conduct, are not malleable or
  ductile, and do not have luster

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Properties of metalloids

• Metalloids have properties similar to both metals
  and nonmetals

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Electronegativity

• Electronegativity is the attraction for an
  electron.
• Metals want to lose electrons when they form
  ions, so they have low electronegativities. The
  larger the metal, the lower the
  electronegativity, since the valence shell is
  farther from the nucleus.
• Nonmetals want to gain electrons, so they have
  high electronegativities. Fluorine is the most
  electronegative. The values are found on table S.

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Atomic Radius

• The radius of the elements increase as you read
  down a group, because another energy level of
  electrons is added.
• The radius decreases across a period, since the
  number of energy levels remains the same, but
  more protons are added to the nucleus, pulling
  the outer shell in closer.

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talmaker/AtomicRadii.html
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A little quiz

• http//www.ilpi.com/genchem/instantquiz.html