Ch. 6: The Periodic Table

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Ch. 6 The Periodic Table
6.1 Organizing the Elements Mendeleev, Periodic
Law, metals, nonmetals, metalloids 6.2
Classifying the Elements squares in the periodic
table, periods and groups (p. 118), electron
configurations, transition elements 6.3 Periodic
Trends atomic size, ions, ionization energy,
ionic size, electronegativityThe properties of
the elements exhibit trends and these trends can
be predicted with the help of the periodic table.
They can also be explained and understood by
analyzing the electron configurations of the
elements. This is because, elements tend to gain
or lose valence electrons to achieve the stable
octet formation. (http//perfectprintables.myfunti
ps.com/documents/printableperiodictable.html)
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6.1 Organizing the Elements
6.1

• Chemists used the properties of elements to sort
  them into groups
• Chlorine, bromine, and iodine have very similar
• chemical properties. (Dobereiner, 1829)

Mendeleev is given credit for an organized table
he arranged the elements in his periodic table in
order of increasing atomic mass.However, there
were many other versions before we accepted
Mendeleevs version. Today, we arrange by atomic
number instead of atomic mass.
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? Alchemy Diderot's Alchemical Chart of
Affinities (1778)
Lavoisier's Table of ? Simple
Substances (1789)
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John Dalton Elements
? A very early notebook (1803)

• A fuller list of
• Dalton's elements
• and symbols
• (1808)

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? Johann Dobereiner's Triads (1780 - 1849)
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? The Telluric Helix or Screw (1862)
Newlands' Octaves (1864)
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Meyer's Periodic Table of 1870
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More examples!
? Mendeleev's Tables of 1869 and 1871
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An Early Version of Mendeleevs Periodic Table
6.1
Newly discovered elements fit into his model.
He published his work early.
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The Periodic Law
6.1

• The periodic law When elements are arranged in
  order of increasing atomic number, there is a
  periodic repetition of their physical and
  chemical properties.
• The properties of the elements within a period
  change as you move across a period from left to
  right.
• The pattern of properties within a period repeats
  as you move from one period to the next.

periods are the rows 1-7 groups or families are
the columns (use IA to VIIIA for representative
elements and noble gases
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Metals, Nonmetals, and Metalloids
6.1

• Metals, Metalloids, and Nonmetals in the Periodic
  Table

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Metals, Nonmetals, and Metalloids
6.1

• Metals are good conductors of heat and electric
  current.
• 80 of elements are metals.
• Metals have a high luster, are ductile, and are
  malleable.

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Metals, Nonmetals, and Metalloids
6.1

• Uses of Iron, Copper, and Aluminum

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Metals, Nonmetals, and Metalloids
6.1

• In general, nonmetals are poor conductors of heat
  and electric current.
• Most nonmetals are gases at room temperature.
• A few nonmetals are solids, such as sulfur and
  phosphorus.
• One nonmetal, bromine, is a dark-red liquid.

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Metals, Nonmetals, and Metalloids
6.1
A metalloid generally has properties that are
similar to those of metals and nonmetals. The
behavior of a metalloid can be controlled by
changing conditions.
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Metals, Nonmetals, and Metalloids
6.1

• If a small amount of boron is mixed with
  silicon, the mixture is a good conductor of
  electric current. Silicon can be cut into wafers,
  and used to make computer chips.

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6.2 Classifying the Elements
6.2

• The periodic table displays the symbols and
  names of the elements, along with information
  about the structure of their atoms.

The background colors in the squares are used to
distinguish groups of elements. The Group 1A
elements are called alkali metals. The Group 2A
elements are called alkaline earth metals. The
nonmetals of Group 7A are called halogens.
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6.2
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Electron Configurations in Groups
6.2

• Elements in groups 1A through 7A are often
  referred to as representative elements because
  they display a wide range of physical and
  chemical properties.
• The s and p sublevels of the highest occupied
  energy level are not filled.
• The group number equals the number of electrons
  in the highest occupied energy level.

Group 1A elements -- there is only one electron
in the highest occupied energy level.
Group 4A elements -- there are four electrons in
the highest occupied energy level.
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Electron Configurations in Groups
6.2

• Elements can be sorted into noble gases,
  representative elements, transition metals, or
  inner transition metals based on their electron
  configurations.

noble gases are the elements in Group 8A
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Representative Elements
6.2
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Transition Elements
6.2

• There are two types of transition
  elementstransition metals and inner transition
  metals. They are classified based on their
  electron configurations.
• In atoms of a transition metal, the highest
  occupied s sublevel and a nearby d sublevel
  contain electrons.
• In atoms of an inner transition metal, the
  highest occupied s sublevel and a nearby f
  sublevel generally contain electrons.

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6.3 Periodic Trends
6.3

• Sodium chloride (table salt) produced the
  geometric pattern in the photograph. Such a
  pattern can be used to calculate the position of
  nuclei in a solid. You will learn how properties
  such as atomic size are related to the location
  of elements in the periodic table.

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Trends in Atomic Size
6.3

• What are the trends among the elements for atomic
  size?
• The atomic radius is one half of the distance
  between the nuclei of two atoms of the same
  element when the atoms are joined.
• In general, atomic size increases from top to
  bottom within a group and decreases from left to
  right across a period.

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Trends in Atomic Size
6.3
atomic size increases from top to bottom within a
group and decreases from left to right across a
period
Size generally decreases
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Ions
6.3

• Positive and negative ions form when electrons
  are transferred between atoms.

• An ion is an atom or group of atoms that has a
  positive or negative charge.
• A cation is an ion with a positive charge.
• An anion is an ion with a negative charge.
• Chlorine gained an electron and becomes an anion
  sodium loses an electron and becomes a cation

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Trends in Ionic Size
6.3

• During reactions between metals and nonmetals,
  metal atoms tend to lose electrons, and nonmetal
  atoms tend to gain electrons. The transfer has a
  predictable effect on the size of the ions that
  form.
• Cations are always smaller than the atoms from
  which they form. Anions are always larger than
  the atoms from which they form.

Relative Sizes of Some Atoms and Ions
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Trends in Ionic Size
6.3
Size generally increases
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Trends in Ionization Energy

• The energy required to remove an electron from
  an atom is called ionization energy.
• The energy required to remove the first electron
  from an atom is called the first ionization
  energy.
• The energy required to remove an electron from an
  ion with a 1 charge is called the second
  ionization energy.

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6.3
Trends in Ionization Energy
First ionization energy tends to decrease from
top to bottom within a group and increase from
left to right across a period.
Energy generally increases
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Trends in Electronegativity
6.3

• Electronegativity is the ability of an atom of an
  element to attract electrons when the atom is in
  a compound.
• In general, electronegativity values decrease
  from top to bottom within a group. For
  representative elements, the values tend to
  increase from left to right across a period.

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What you need to know Ch. 6

• What is the underlying cause of periodic trends?
  
• The trends that exist among these properties can
  be explained by variations in atomic structure.
• Ch. 6 packet (worksheets, periodic table
  activity, elements videos)
• Vocabulary group or family, period metals,
  nonmetals, metalloids alkali metals, alkaline
  earth metals, halogens noble gases,
  representative elements, transition metals, inner
  transition metals atomic radius, cation, anion,
  ionization energy, electronegativity
• For examplecan you talk about period, group,
  family, energy levels, valence electrons,
  electron configuration, cations, anions, metals,
  non-metals, metalloids, transition elements,
  alkali metals, alkaline earth metals, halogens,
  noble gases, lanthanides, actinides,
  representative elements, Mendeleev, trends
  (atomic radius, ionization energy, valence
  electrons, electronegativity)?