Unit 4: Periodic Table

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Unit 4 Periodic Table Periodic Trends

• EQ How does the organization of the periodic
  table allow us to make predictions or determine
  the behavior properties of elements?

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GPS

• SC4. Students will use the organization of the
  Periodic Table to predict properties of elements.
• a. Use the Periodic Table to predict periodic
  trends including atomic radii, ionic radii,
• ionization energy, and electronegativity of
  various elements.
• b. Compare and contrast trends in the chemical
  and physical properties of elements and
• their placement on the Periodic Table.

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Key Vocabulary Terms

• Law of Octaves
• Periodic Table
• Periodic Law
• Periods
• Group/ Family
• Valence Electron

• Periodic Trends
• Atomic Radius
• Ionic Radius
• Ionization Energy
• Electronegativity
• Electron Affinity

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The History

• Dobereiner
• Found elements could be put in Triads
• Newlands
• Discovered the Octet Rule when classifying
  elements
• Mendeleev
• First to organize elements by increasing mass to
  create the Periodic Table

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J. W. Dobereiner (1780-1849)

• Observed that several elements could be
  classified into sets of three a.k.a. Triads
• His Triads included.
• Lithium, Sodium, and Potassium
• Calcium, Strontium, and Barium
• Chlorine, Bromine, and Iodine

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Triads

• Grouped By Similar Chemical Properties
• Many Properties of Middle Elements Are
  Approximate Averages Of The Properties Of The 1st
  And 3rd Element

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EXAMPLE
ELEMENT ATOMIC MASS Density
Cl 39.5 1.56
Br 79.9 3.12
L 126.9 4.95
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J.A.R. Newlands (1837-1898)

• Presented the idea that when the elements were
  arranged in order of increasing atomic mass, the
  properties of every eighth element was like that
  of the first in the set1st-8th, 2nd-9th, and so
  on
• Called the pattern the law of octaves

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Dmitri Mendeleev (1834-1907) Lothar Myer
(1830-1895)

• Published nearly identical schemes for
  classifying the elements
• Mendeleev is given more credit since he published
  first and was more successful at demonstrating it
• Mendeleev also put breaks in the Table where
  other elements were yet to be found b/c he knew
  they had to fit in to make the table work right

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Mendeleev

• Noticed that when he arranged the elements by
  increasing atomic mass he could see a periodic
  repetition of their properties
• Used this to create the first Periodic Table

• Wanted to make the elements easier to learn and
  understand

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Moseley

• Moseley
• Developed atomic number concept for the atom
• Arranged elements by increasing atomic number
  rather than mass as Mendeleev had

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The Periodic Law

• when elements are arranged in order of
  increasing atomic number, their physical and
  chemical properties show a periodic pattern

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A. Periodic Law

• When elements are arranged in order of increasing
  atomic , elements with similar properties appear
  at regular intervals.

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Reading the Table

• Groups/Families are elements with similar
  properties and run up and down. There are 18
  families.
• Periods run left to right on the table. There
  are 7 periods.

• Groups to remember
• (1)- Alkali Metals
• (2)- Alkaline-earth Metals
• (3-12)- Transition Metals d-block
• Inner transition Metals (bottom) f-block
• (17)-Halogens
• (18)- Nobel Gases

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Reading the Table (Cont.)

• Metals
• Have luster (a shine)
• Good conductors (of heat electricity)
• Solids usually
• Malleable (can be pounded into sheets)
• Ductile (pulled into a wire)

• Nonmetals
• No luster
• Poor conductors
• Many are Gases
• Big variation in physical properties

• Metalloids/ semi-metals
• --Have properties of metals and nonmetals
• -form the steps except Al.

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Electrons and The Table

• Electrons fill atoms in s-, p-, d- and f-
  orbitals. These orbitals have a location on the
  P.T.
• S-block left side.
• P-block right side.
• D-block Transition Metals.
• F-block Inner Transition Metals.

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Classification of the Elements

• The periodic table is divided into blocks that
  correspond to the sub-levels that are being
  filled with electrons
• S block Group 1 2
• P block Groups 13-18 (except for Helium)
• D block transition metals
• F block inner transition metals

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Classification of the Elements

• The periodic table is one of the most important
  tools in chemistry
• Elements are arranged according to atomic number,
  but the periodic table also relates to atomic
  structure and trends among the elements
• Elements can be classified into 4 categories
  according to their electron configurations

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Classification of the Elements

• The noble gases
• Elements in which the outermost s and p sublevels
  are filled
• Also known as inert gases
• The representative elements
• Elements in which the outermost s or p sublevel
  is only partially filled
• Usually called the Group A elements
• Group 1 elements are the alkali metals
• Group 2 elements are the alkaline earth metals

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Important Group names

• Alkali Metals
• Alkaline Earth Metals
• Transition Metals
• Halogens
• Noble Gases

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Classification of the Elements

• The transition metals
• Metallic elements in which the outermost s
  sublevel and nearby d sublevel contain electrons
• Called the Group B elements
• Characterized by the addition of electrons to the
  d orbitals
• The inner transition metals
• Metallic elements in which the outermost s
  sublevel and the nearby f sublevel generally
  contain electrons
• Characterized by the filling of f orbitals