Periodic Table

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Periodic Table
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(No Transcript)
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History of the Periodic Table
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• Dmitri Mendeleev

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Mendeleevs Periodic Table
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Arrangement of Periodic Table

• Periodicity recurrent trends seen in the
  elements

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Periods

• horizontal rows
• 1 - 7
• Period number indicates which energy level holds
  the valence electrons

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2
3
4
5
6
7
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Groups/Families

• vertical columns
• 1-18
• elements in the same group share chemical
  properties
• Main group elements
• Groups 1,2 13, 14, 15, 16, 17,
  18

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Types of Elements
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Metals

• Most are silver, shiny, solid, malleable, ductile
  good heat/electrical conductors

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Nonmetals

• Brittle (solids), dull, non-conductors, and exist
  in all three states (solids, liquids, gases)

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Metalloids

• Elements found along the stair-step between
  metals and nonmetals, does NOT include Al
• Properties are in between metals nonmetals
• Silicon (Si) is probably the most well-known
  metalloid.

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Color Groups of the Periodic Table
Metalloids
Noble Gases
Alkali Metals
Halogens
Transition Metals
Alkaline Earth Metals
Also called inert gases because they do not react
Inner Transitional Metals
Lanthanide Series
Actinide Series
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Properties and Electron Configuration

• Each group (column) ends with the same electron
  configuration. This determines many of the
  physical properties that the group share.

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Alkali Metals with Water
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Halogen
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Noble Gases

• odorless
• colorless 

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Periodic Table Trends

• Patterns on the periodic table
• Atomic Radius
• Ionic Radius
• Electronegativity
• Ionization Energy
• Reactivity

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Explaining the trends

• Effective Nuclear Charge (Zeff)
• The relative attraction the
• valence electrons have for the
• Protons in the nucleus.
• Electron Shielding Effect-
• Inner shell electrons 
• blocking valence electrons 
• from the positively charged nucleus
• Watch this video

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Atomic Radius

• Atomic radius is half the distance between the
  centers of two atoms, measured in angstroms
  (1x10-10 m).

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Atomic Radius Trend

• Atomic radius increases as you move down a group
• Atomic radius decreases as you move from left to
  right in a period

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Atomic Radius Trend
Across the period, the number of protons
increases while the number of shielding electrons
stays the same. (Zeff increases) This make the
nucleus pull in the valence electrons. That
makes for a smaller atom.
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Atomic Radius Trend
Down the group, the number of energy levels
increases so the number of shielding electrons
increases. The nucleus cannot pull in the
valence electrons. That makes for a bigger
atom.
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Ionic Radius
Metals lose electrons to form cations
Ionic radius is smaller than atomic radius
because an energy level is lost or shed
Nonmetals gain electrons to form anions
Ionic radius is larger than atomic radius because
the electrons outnumber the protons. The nucleus
has less control of the valence electrons.
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Electronegativity

• Electronegativity is a measure of how strongly
  atoms attract bonding electrons to themselves
• An assigned number rates the electronegativity
  (from 0.7 to 4.0)
• Low electronegativity cannot attract valence
  electrons
• High electronegativity can attract valence
  electrons

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Electronegativity Trend

• Electronegativity values increase as you move
  from left to right in any period.

Biggest IE Fluorine Smallest IE Francium
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Electronegativity Trend

• Within any group, electronegativity values
  increase as you go up.

Biggest IE Fluorine Smallest IE Francium
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Period 2 elements Large ? low EN
small ? high EN
O 8p
F 9p
From right to left, Zeff increases. In small
atoms, the distance from the nucleus to available
electrons is short, therefore the nucleus has a
strong attraction (pull) for electrons.
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Group 17 elements small ? high EN
large ? low EN
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Ionization Energy

• Ionization Energy the energy needed to remove
  the outermost electron in an atom describes how
  hard it is to steal an electron from an atom
• Increases as you go from bottom to top in a group
• As you move up a group, the number of energy
  levels decreases. The nucleus of small atoms has
  a stronger hold on its electrons because they are
  so close.

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Ionization Energy Pattern

• period 2 elements
• IE Increases as you go right in a period
• Larger Zeff from right to left
• Atom is smaller outer electrons are closer to
  the nucleus

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Ionization Energy Trend

• Increases as you go from bottom to top in a group
• As you move up a group, the number of energy
  levels decreases. The nucleus of small atoms has
  a stronger hold on its electrons because they are
  so close.

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Metal Reactivity Trend

• Based on the attraction the metal has for the
  nonmetals electrons.

The most reactive metal is francium
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Nonmetal Activity Trend

• Non-Metal Activity refers to how easily nonmetals
  gain e- to form anions
• This trend does not include the noble gases,
  because they are non-reactive

increasing nonmetal activity
increasing nonmetal activity
The most reactive nonmetal is fluorine