3.2 Using the Periodic Table

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3.2 Using the Periodic Table
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Objectives

• Relate an elements valence electron structure to
  its position in the periodic table.
• Use the periodic table to classify an element as
  a metal, nonmetal, or metalloid.
• Compare the properties of metals, nonmetals, and
  metalloids.

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New Vocabulary to Look for

• Period
• Group
• Noble gas
• Metal
• Transition element
• Lanthanide
• Actinide
• Nonmetal
• Metalloid
• semiconductor

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Relationship of the Periodic Table to Atomic
Structure

• Periodic tables contain a vast array of
  information on the elements.
• You will learn to use the periodic table to
  gather information about the elements and group
  of elements we are studying.
• Modern periodic table is arranged according to
  increasing atomic number.
• What information does the atomic number tell us?

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Periods and Groups

• The horizontal rows of the periodic table are
  called periods.
• The vertical columns are referred to as groups.
• Groups are also called families of elements.
• Elements in the same group have similar
  properties.

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Atomic Structure of Elements Within a Period

• Each period starts with a group 1 element, which
  has 1 valence electron.
• As you move across a period the number of valence
  electrons increases. Moving from 1, 2, 13, 14,
  15, 16, 17, 18.
• Group 1 elements have one electron at a higher
  energy level than the noble gas of the preceding
  period.

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Atomic Structure of Elements Within a Group

• The number of valence electrons can be predicted
  using the periodic table.
• Group 1 has 1 valence electron
• Group 2 has 2 valence electrons
• Groups 13-18 have the second digit of valence
  electrons.
• 13 has 3 valence electrons
• 14 has 4 valence electrons
• Fig. 3.8 p. 98

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Noble Gases

• Group 18 have the periodic table.
• They have 8 valence electrons, except for He
  which only has 2
• Full energy levels
• Generally unreactive or inert
• Ne, He, Ar

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Noble Gases
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Halogens

• Greek meaning salt former
• Form salt like compounds
• Group 17
• 7 valence electrons
• F, Cl, Br, I

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Alkali Metal

• Group 1 (except H)
• 1 valence electron
• Li, Na, K

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Alkali Metals
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Alkaline Earth Metals

• Group 2
• 2 valence electrons
• Be, Mg, Ca, Ba

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Valence Electrons-Properties

• Valence electrons help to determine the physical
  and chemical properties
• Groups have similar properties b/c they have the
  same number of valence electrons
• Fig. 3.9 p. 99 Electrons in Energy Levels-Group 16

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Physical States and Classes of Elements
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Physical States of the Elements

• The physical states of the elements are show on
  the periodic table on p. 92-93.
• Most elements are solids at room temperature
• Only two are liquids. What are they?
• A.
• B.
• All the gases except hydrogen are in the upper
  right corner of the table. List some.

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Gallium
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Classifying Elements

• Elements are classified into groups
• Metals
• Nonmetals
• Metalloids
• Majority of elements are metals
• Left side and center
• Nonmetals
• Upper right corner
• Metalloids
• Along the boundary b/t metals and nonmetals

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Metals

• Have luster
• Conduct heat
• Good conductors of electricity
• Most have high boiling pts.
• Malleable
• Ductile
• Most are solid
• Only one metal is in the liquid state.

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Metals

• Most are located in Groups 1-13
• Transition Elements- Elements in Group 3-12 (all
  metals)
• Iron (Fe), nickel (Ni), Copper (Cu), Zinc (Zn)
• Some of period 7 are synthetic and radioactive
• The transition elements have a less predictable
  behavior and properties than the other metals

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Transition Elements
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Transition Elements
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Transition Elements
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Metals

• Elements with the atomic numbers 58-71 and 90-103
  are placed below the main table
• If they were part of the main table it would be
  extremely wide
• Known as the inner transition elements
• Many were unknown in Mendeleevs time

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Inner Transition Elements
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Lanthanides

• First series of inner transition elements
• 14 elements 58-71
• Also called rare earth elements- abundance 0.01
• All have similar properties

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Actinides

• Second series of inner transition elements
• 90-103
• Radioactive
• None beyond uranium occur in nature
• Unpredictable-complex structures

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Nonmetals

• Nonmetals are abundant in nature
• Oxygen and nitrogen make up 99 of our atmosphere
• Carbon is found in more compounds than all the
  other elements combined.

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Nonmetals

• Dont conduct electricity
• Poor conductors of heat
• Brittle when solid
• Many are gases at room temp.
• Solids lack luster
• Melting points and boiling points are low
• Table 3.5 p. 105 Properties of Metals and
  Nonmetals

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Metalloids

• Have properties of both metals and nonmetals
• Located between the metals and nonmetals
• Si, Ge and As are semiconductor
• Does not conduct electricity as well as a metal,
  but does better than a nonmetal
• Si semiconductors made the computer revolution
  possible.

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Atomic Structure of Metals, Metalloids and
Nonmetals

• Differences occur b/c of the different
  arrangements of electrons
• Number, arrangement of valence electrons along
  with how tightly they are held in the atom
  determines the behavior.

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Valence electrons in Metals

• Loosely bound
• Free to move in the solid metal
• Easily lost
• Freedom of movement conductivity

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Valence electrons in Nonmetals and Metalloids

• Tightly held
• Not easily lost

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Chemical Reactions and Electrons

• Metals tend to lose valence electrons
• Nonmetals tend to share or gain electrons

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General Properties and Uses of Metals, Nonmetals
and Metalloids

• Familiar Metals
• Jewelry, figurines, electrical circuits
• Some Lanthanides and Actinides
• Compounds of europium and ytterbium picture
  tubes of TV
• Neodymium high powered lasers
• Carbon and Some Other Nonmetals
• Carbon Coal, natural gas, oil, graphite,
  diamonds
• Bromine and Iodine halogen lamps
• Metalloids
• Silicon electronic devices
• Page 106-107

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Semiconductors

• Metalloids that do not conduct electricity as
  well as metals, but better than nonmetals
• Uses
• Television
• Computer
• Handheld electronic games
• Calculators

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Semiconductors Electrons and Electricity

• An electrical current is flowing electrons.
• Metals conduct electricity well because the
  electron are not tightly held by the nucleus and
  are therefore free to move.
• Copper wire
• At room temperature Si is not a good conductor.
  Its four electrons are tightly held by the
  nucleus.
• In order to make it a good conductor it must be
  doped with another element.

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Silicon (Si)
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Doping of Si

• By adding small amounts of P to Si a good
  conductor is created.
• P has five valence electrons. This adds an extra
  electron which is free to move electrical
  conductivity.
• n-type semiconductor (negatively charged)

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Doping of Si

• By adding B to Si a good conductor is created
• B has three valence electrons. The shortage of
  electrons creates holes in which the electrons
  can move electrical conductivity.
• p-type semiconductor (positively charged)

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Diodes

• The combination of n-type and p-type
  semiconductors is a diode.
• Permits electrical flow in only one direction
• Negative terminal to positive terminal

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Transistors

• Key components in electrical circuits, amplifying
  the electrical signal.
• npn-junction
• pnp-junction

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Review

1. Where are the halogens, noble gases, alkali
   metals, alkaline earth metals, lanthanide and the
   actinides located? Give me an example of each?
2. What are the characteristics of a metal, nonmetal
   and metalloid?
3. How many valence electrons does Li have?

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Using the Periodic Table
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