The Periodic Table Chapter-6

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The Periodic TableChapter-6
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Main Concepts

• Main Concepts
• Development of the Periodic Table
• Electron Configurations and the Periodic Table
• Periodic Trends
• Ionization Energy
• Electron Affinity
• Electronegativity
• Atomic Radius
• Ionic Radius

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The Periodic Table

• By 1860, 63 elements had been discovered and
  scientist started to notice patterns with the
  elements.
• Stanislao Cannizzaro developed a method for
  measuring atomic masses that leads to the
  standardization of atomic masses.
• In 1869, Dmitri Mendeleev organized the elements
  into a periodic table based on atomic masses and
  grouped the elements by similarities in their
  chemical and physical properties.

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The Periodic Table

• Mendeleev demonstrated that elements have
  predictable properties that followed a repeating
  pattern.

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The Periodic Table

• Mendeleev predicted the existence and properties
  of new elements and pointed out accepted atomic
  weights that were in error.
• He stated that if the atomic weight of an
  element caused it to be placed in the wrong
  group, then the weight must be wrong. He
  corrected the atomic masses of Be, In, and U.
• Mendeleev was so confident in his table that he
  used it to predict the physical properties of
  three unknown elements.

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The Periodic Table

• These three unknown elements (Sc, Ga, and Ge)
  were discovered between 1874-1885 and were very
  close to the actual values he predicted leading
  to the general acceptance of his periodic table.
• When discrepancies arose between atomic masses
  and properties (Ar/K, Co/Ni, Th/Pa, Te/I), the
  elements in question were grouped by similar
  properties.

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The Periodic Table

• In 1913, Henry Moseley discovered that the
  positive charge of the nucleus increased by one
  unit from one element to the next.
• He proposes that the elements in the periodic
  table be arranged in order of increasing atomic
  number instead of atomic mass.
• Moselys work provided experimental proof for
  Mendeleevs ordering of the periodic table by
  properties.

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The Periodic Table

• Moseleys work lead to the modern definition of
  atomic number and that atomic number and not
  atomic mass is the basis for the organization of
  the periodic table.

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The Periodic Law and Periodicity

• Periodic Law The physical and chemical
  properties of the elements are periodic functions
  of their atomic number.
• Periodicicity When elements are arranged in
  order of increasing atomic number, elements with
  similar properties recur at regular intervals.

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The Periodic Table

• 1894-1910 William Ramsay discovers argon, neon,
  and isolates helium for the first time.
• To fit these elements into the Periodic Table,
  Ramsey proposed a new group between 17 (fluorine
  family) and Group I (lithium family). By 1910
  all the noble gases are discovered.

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Chemistry in Action Discovery of the Noble Gases
Sir William Ramsay
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Periodic Trends

• Ionization Energy
• the energy required to remove one or more
  electrons from an atom to form a cation.
• Electron Affinity
• the energy change that occurs when an electron
  is accepted by an atom to form an anion.
• Electronegativity
• the measure of the ability of an atom to attract
  electrons.

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Periodic Trends

• Atomic Radius
• one half the distance between the nuclei of
  adjacent atoms.
• Ionic Radius
• one half the diameter of an ion in an ionic
  compound.

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Periodic Trends Ionization Energy

• Ionization Energy
• the energy required to remove one or more
  electrons from an atom or ion measures how
  strongly an atom holds on to its electrons.
  Ionization energy is always endothermic and forms
  cations.
• First ionization energy
• A energy ? A e-
• Na energy ? Na e-

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Ionization Energy

• Second ionization energy
• A energy ? A2 e-
• Mg energy ? Mg2 e- or
• Mg energy ? Mg2 2e-

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Periodic Trends Ionization Energy

• Removal of 1st electron 1st ionization energy
• Removal of 2nd electron 2nd ionization energy
• Removal of 3rd electron 33d ionization energy
• Ionization energy increases as successive
  electrons are removed from ions resulting in
  higher positive charges.

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Ionization Energy of Carbon
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Ionization Energy

• Ionization Energy (kJ/mol)
• 1st 2nd 3rd 4th
• Li 520 7300 11815
• Na 496 4562 6912 9544
• K 419 3051 4411
• Mg 738 1451 7733 10540
• Ca 590 1145 4912 
• Al 578 1817 2745 11578

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Ionization Energy
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Ionization Energy
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Ionization Energy
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Practice Ionization Energy

• Choose the elements for the following energies
  Ne, Ga, C, Ba, P, O, W, Pb, Se, I, Rb
• 1st 2nd 3rd 4th 5th 6th
  7th
• 899 1757 14850 21005 34000 42000
  55000
• Ba or W (group 2, d or f block)
• 1086 2350 4620 6220 38000 47261
  56,800
• Pb or C (group 14)
• 1314 3390 5300 7470 11000 13000
  71320
• Se or O (group 16)

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Practice Ionization Energy

• Choose the elements for the following energies
  Ne, Ga, C, Ba, P, O, W, Pb, Se, I, Rb
• 1st 2nd 3rd 4th 5th 6th
  7th
• 578 1820 2750 11600 14800 18400 22600
• Ga (group 13)
• 1012 1904 2910 4960 6240 21000 24400
• P (group 15)
• 2080 3950 6120 9370 12220 15000 18000
• Ne (group 18)

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Practice Ionization Energy

• Choose the elements for the following energies
  Ne, Ga, C, Ba, P, O, W, Pb, Se, I, Rb
• 1st 2nd 3rd 4th 5th 6th
  7th 8th
• 1680 3375 6045 8408 11020 15160 17860 92010
• I (group 17)
• 403 2632 3860 5200 8240 12100 18760 24360
• Rb (group 1)

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8.4
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Electronegativity

• Electronegativity the measure of the ability of
  an atom in a chemical compound to attract
  electrons.
• Developed by Linus Pauling, electronegativity is
  related to the ionization energy and electron
  affinity of an atom in a molecule.
• Elements with a high electronegativity have a
  greater tendency to attract electrons than
  elements with a low electronegativity.

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Electronegativity Linus Pauling

• Electronegativity is a measure of the ability of
  an atom in a molecule to attract electrons to
  itself.

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Electronegativity

• Fluorine (F) the most electronegative element
  is arbitrarily assigned an electronegativity
  value of 4. In general, nonmetals are more
  electronegative than metals.
• Electronegativity is used to determine bond
  polarity which describes the degree of sharing of
  electrons between atoms.

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Atomic Radius

• Atomic Radius one half the distance between the
  nuclei of identical atoms joined in a molecule.
  Electron cloud determines the size of the atom
  but the boundary varies.

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8.3
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Atomic Radius
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Atomic Radius
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8.3
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Atomic Radii
8.3
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Ionic Radius

• Ionic Radius is one half the diameter of an ion
  in an ionic compound.

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Ionic Radius
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Ionic Radius

• Cation positive ion formed by metals giving up
  electrons. Formation of a cation by the loss of
  an electron/s leads to a decrease in radius. The
  remaining electron cloud is smaller and closer to
  the nucleus.

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Ionic Radius
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Ionic Radius

• Anion a negative ion formed by a nonmetal
  gaining electrons. Formation of an anion by a
  gain in electrons leads to an increase in ionic
  radius. The electron cloud spreads out because
  there is a smaller attractive force on the
  electrons from the nucleus and greater repulsion
  forces between them.

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Ionic Radius
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Atomic/Ionic Radius
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Electron Configuration Practice

• Determine the element or ending electron
  configuration.
• 3p4
• 5p1
• xenon
• 5s1
• vanadium
• 5f3
• 3d8
• lawrencium (Lr)

• iridium
• 5s2
• mercury
• 3p5
• 4p6
• 3f6
• 5f2
• 6d5

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Electron Configuration Practice

• a) 2s22p5, b) 5s24d105p5, c) 2s22p2,
  d) 6s25d106p5, e) 2s22p4
• Which element/s are in the same block?
• Which element/s are in the same period?
• Which element/s are in the same group?
• Which element has the highest electron affinity?
• Which element/s would form a -1 ion?
• Which element/s would form a -4 ion?
• Which element/s would form a 3 ion?
• Which element/s would form a -2 ion?

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Electron Configuration Practice

• a) 2s22p5, b) 5s24d105p5, c) 2s22p2,
  d) 6s25d106p5, e) 2s22p4
• Which element has the highest electronegativity?
• Is the atomic or ionic radius larger for e?
• Which element/s has seven valence electrons?

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Electron Configuration Practice

• 1s22s22p63s23p2
• Group number?
• Period number?
• Block?
• Type of element?
• Charge of the most common ion?

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Electron Configuration Practice

• 1s22s22p63s23p64s23d104p65s24d105p66s24f5
• Name of element?
• Period element is in?
• Block?
• Energy level?
• Type of element?
• Charge of the most common ion?

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Periodic Trend Practice

• Cr (z 24) Al (z 13) Ti (z 22)
• Smallest atomic radius?
• Smallest electronegativity?
• Largest ionic radius?
• I (z 53) N (z 7) S (z 16)
• Smallest atomic radius?
• Largest electronegativity?
• Largest ionic radius?

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Periodic Trend Practice

• Mn Mg Ge Ba.
• Which element/s has electronegativity greater
  than Zn.
• Which element would most easily form an anion? 
• Which element has the smallest electron affinity?
• Which element has the largest atomic radius?

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Periodic Trend Practice

• Ni Cl Li Fe.
• Largest 1st ionization energy?
• Largest 2nd ionization energy?
• Largest ionic radius?
• Most easily forms a cation?
• Arrange in order of increasing size.
• Which is larger Ni atom or Ni ion?
• Which is smaller Cl atom or Cl ion?
• Which is larger Ni ion or Cl ion?

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Current Periodic Table
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